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PNW Drawing Regrinder Machine

Posted by yonni1967 on July 7, 2013

APAKAH REGRINDER MESIN ITU ?

Klik disini untuk PDF Files Regrinder explained in word

ortho iso
Mesin regrind berasal dari kata ‘Re’ yaitu kembali dan ‘Grind’ yang berarti menggiling.
Secara harfiah dapat diartikan sebagai menggiling kembali. Dalam konteks buku ini kita akan
fokuskan arti ‘giling-menggiling’ dalam bidang Plastik.
Apakah anda pernah mendengar kata ‘Daur ulang Plastik’ ?. Jika anda belum pernah
mendengarnya, salah satu jenis mesin yang akan kita perbincangkan ini termasuk salah satunya.
Ada banyak metode daur ulang plastik, intinya dalam proses tersebut adalah pekerjaan
membuat waste / afvalan plastik bekas menjadi material atau bahan untuk siap dicetak
kembali menjadi produk yang baru. Umumnya material plastik murni berbentuk granula ( bijih
plastik ). Granula diproduksi oleh pabrik granulator yang berskala besar dan tentunya hanya
Industri Plastik saja yang dapat membelinya untuk berbagai kemasan plastik.
Untuk diolah menjadi produk yang baru umumnya bahan ex regrind diolah lagi pada mesin
Injection Moulding, Blow Moulding atau Stretching. Kita tidak membahas mesin-mesin tersebut
karena butuh investasi besar. Jadi mesin regrind yang kita perbincangkan adalah salah satu mesin
suporting utama yang lebih kecil dari segi dimensi dan segi investasi. Dan mesin yang saya
kemukakan ini bisa dibilang lebih kecil lagi bila berbicara dimensi dan sekala.
Singkat cerita, kita sebut saja mesin Regrind adalah mesin giling plastik serba guna. Kalau
boleh saya unggulkan pada desain saya tersebut adalah dimensi atau ukurannya yang kecil
sehingga sangat cocok dioperasikan pada usaha home industri. Mesin giling ini dapat dioperasikan
dengan motor induksi 1 phase, 3 phase atau dapat dihubungkan dengan penggerak lain seperti
diesel mini yang tentunya lebih kuat tenaganya. Pada awalnya mesin ini saya desain untuk
penggerak motor 1 phase dengan power 1 HP atau 746 Watt, jadi mampu dioperasikan di rumah
tangga. Apabila diinginkan kapasitas lebih besar dari itu, dari drawing yang akan saya berikan
nanti tinggal menambah sekalanya.
Dari desain aslinya mesin dapat menangani segala material plastik bekas maupun baru
sehingga siap dipasarkan pada konsumen. Material plastik yang dapat digiling adalah : HDPE,
LDPE , SAN, PE, dan masih banyak lagi yang lainnya.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

MENGAPA INVEST MESIN REGRIND ?
Invest mesin Regrind sangat menguntungkan !. Mengapa ?. Karena …….
1. Belum banyak orang melirik peluang usaha sekala kecil mengolah waste plastik / rosokan
plastik yang terbuang setiap hari. Secara pribadi penulis telah mengamati limbah plastik
ada dimana-mana di sekitar kita, di jalan, terminal atau di bak-bak sampah rumah tangga.
Bagaimana dengan para pemulung ? Mereka telah mengumpulkannya dan menyetorkan
perkiloan pada pengepul tapi hanya sebatas itu. Mereka belum sampai pada tahap
mengolahnya kembali menjadi bahan baku plastik recycle bersih yang tentu lebih mahal
harganya. Di dalam suatu rumah tangga kecil secara tanpa sadar dalam satu bulannya
membuang rata-rata minimal 3 Kg plastik afvalan yang berasal dari tas kresek, botol air
mineral, bungkus kosmetik dan masih banyak lagi. Pada hitungan sederhana, bila satu
tahun dalam satu rumah tangga membuang afvalan plastik seberat 36 Kg dan jika harga
plastik afvalan saat tulisan ini dibuat seharga Rp 2.500,- maka didapat harga sebesar Rp
90.000,- / tahunnya. Sedangkan harga plastik ex regrind saat ini ± Rp 14.000,-. Bila diolah
menjadi bahan baku ex regrind akan didapat laba Rp 11.500,-. Jadi dalam setahun dalam
satu rumah tangga akan dapat dikumpulkan laba sebesar Rp 138.000,-. Bayangkanlah bila
anda dapat nego collect afvalan dalam satu RT sebanyak 70 KK didapat laba Rp 96.660.000
kotor. Apabila dihitung perbulan didapat penghasilan sebesar Rp 805.000,-. Ini adalah
perhitungan kecil dan paling terkecil dalam bisnis plastik ex regrind. Penghasilan nyata
tentunya yang mempengaruhi adalah dari kuantitas dan kualitas plastik ex regrind dan
fluktuasi harga pembelian dan penjualan. Tolong dicatat pula bisnis plastik adalah bisnis
yang menggiurkan setelah kertas, karet dan air, tidak mudah busuk dan lebih baik dari
jualan beras atau gula sekalipun.
2. Pertimbangan environment atau lingkungan sekitar kita yang kurang peduli dan belum
terorganisir memanfaatkan limbah plastik menjadi bahan yang siap didaur ulang.
3. Sebagai penambah sumber penghasilan / income dan alternatif peluang usaha yang
membuka lapangan pekerjaan baru.
4. Sebagai supplier raw material plastik dimana pertumbuhan usaha plastik semakin
meningkat permintaannya.
5. Membantu program pemerintah atau badan dunia yang dewasa ini sedang galak-galaknya
kampanye “ Go Green “.
Dalam perkembangan industri pengolah daur ulang limbah bahan plastik bekas memang
sudah ada yang bersekala besar dan tumbuh seperti di kawasan Sepanjang Sidoarjo, Surabaya
atau di Pasuruan. Kendala utama dari usaha ini memang bau yang dihasilkan dari bahan baku.
Untuk peluang home industri yang saya kemukakan disini adalah murni home industri yang bebas
bau dan berisik karena yang akan kita olah hanyalah plastik bekas rumah tangga saja. Bila boleh,
disejajarkan setara dengan kalau kita memiliki barang rumah tangga lumrah lain seperti : Blender,
mixer atau mesin penyabit rumput.
Sekarang marilah kita pelajari drawing mesin “ REGRINDER MACHINE “ hasil desain saya
dibawah. Untuk diketahui penulis telah berkecimpung dibidang permesinan plastic packaging
selama 21 tahun, jadi dapat direferensikan.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

ASSEMBLING “E”
Berikut adalah pengenalan scene assembling “E”, inti dari mesing penggiling / pencacah
plastik bekas (Regrind). Masing-masing parts saya explode sehingga anda mudah mengenali
beberapa komponennya.
Ada empat buah Blade atau pisau giling yang berputar dengan speed min 1500 RPM. Hasil
cacahan plastik yang digiling akan lari kebawah dan akan disortir oleh mesh filter (3) sedangkan
yang tidak lolos masuk ke mesh akan dibawa putar lagi keatas oleh Blade dan dicacah lagi sampai
habis menjadi semacam granule.
Motor penggerak dalam drawing sengaja tidak saya sertakan dengan tujuan memberi
kebebasan anda untuk memodifikasi dikemudian hari, namun saya saya sarankan harus
menggunakan electric motor minimal bertenaga 1HP / 746 Watts. Pengkopelan antara motor dan
pulley ‘A’ menggunakan sabuk daya atau V wedge belt yang biasa dijual ditoko-toko alat mobil.
Penggunaan motor bakar semacam penggerak ber-BBM sedapat mungkin anda hindari
karena akan mencemari lingkungan rumah. Untuk itulah dengan penggerak mini saya desainkan
perlunya Balast untuk membantu electric motor agar lebih ringan kerjanya saat mesin
beroperasional.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

ASSEMBLY “ C “

explode basic assembly E

Pada scene berikut anda akan kami bawa pada explode drawing rumah dari pada Rotary
crusher diatas. Berikut adalah kurang lebih pemandangan assembly housing :
Pertama yang akan saya jelaskan tentu saja gambaran bagaimana bisa plastik bekas dari
berbagai ukuran dapat masuk kedalam housing dan dirajang oleh rotary crusher ?. Anda tidak
perlu memilahnya secara dimensi, cukup apabila ukuran bahan plastik bekas dapat masuk dalam
hopper rotary crusher akan mencabiknya kedepan dan dimampatkan pada dinding Deck 2_1.
Belum ada celah saat bahan tertumbuk pada permukaan 2nd Blade slider. Hasil tabrakan tersebut
akan memaksa rajangan memasuki celah di ketiak rotary crusher. Seperti keterangan diatas
rajangan yang tidak lolos akan dibawa keatas lagi pada siklus berikutnya.
Untuk menghindari kemacetan atau jammed saya desainkan 2nd Slider dapat disetel maju
mundur sekaligus untuk setting ketebalan rajangan agar seragam. Perlu diperhatikan adalah
kerenggangan mesh juga dapat diatur naik turun melalui baut yang dipasang pada 2nd Blade
holder.
Jadi antara 2nd blade slider dan holder jangan lupa terkopel melalui perantara spring yang
tidak saya perlihatkan disini. Mengapa demikian ?, sekali lagi saya juga memberi kebebasan anda
untuk improvisasi, inovasi atau modifikasi sendiri. Mesin tidak membutuhkan vibrate device
karena getaran rajangan mesin sudah cukup untuk menyaring hasil gilingan plastik kebawah.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

ASSEMBLY “ B “
Assembling “ B “ dibawah adalah “ dudukan” atau holder dimana rakitan assembling “ E
“ dan assembling “ C “ bertemu menjadi satu. Bisa dikatakan berikut ini adalah sasisnya!.
Kesatuan assembling “ E “ dan “ C “ nantinya akan nongkrong di drawing atas. Seperti yang
dijelaskan suatu saat mesin tidak dapat dihindari yang namanya macet atau “ Jammed “. Pada
situasi seperti itu diperlukan penanganan cepat untuk membongkar jantung mesin.
Anda tidak perlu kuatir !, desain ini mengantisipasinya dengan engsel “ Hinge “ dan “ Lock
“ . Cara bekerjanya adalah dengan melepas kedua “ Lock “ dan unit diatasnya akan menganga
karena ada engsel “ hinge “ menunggu operator membebaskan sumber penyebab kemacetan
tersebut.
“ Lock “ juga berfungsi menjamin mesin aman saat mesin lagi beroperasional. Fungsifungsi
tersebut juga berlaku saat mesin perlu untuk pembersihan dan maintenance, tapi jangan
lupa saat melakukan itu cabut steker dari stop kontak demi keamanan.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

ASSEMBLY “ D “
Assembly berikut ini adalah penggabungan ketiga sub component diatas dengan cover yang
dinamakan Feeding / Hopper.
Seperti yang terlihat pada drawing diatas, cup cover (1) adalah tutup cover loader (2).
Bahan bisa dibuat dari plat BJLS atau yang lain setebal 1 s/d 2 MM tergantung selera anda. Agar
saat bahan tidak terpental keluar saat proses penggilingan bahan diujung atas sengaja dibuat
berbelok.
Ada baiknya dibuatkan engsel agar buka tutup cup cover selalu tertutup otomatis setelah
cup dibuka. Penting bagi operator baru, peringatan bahan dapat terpental keluar dan melukai
seseorang bila cup cover dibiarkan menganga.
Dalam industri plastik sekala besar, daya yang digunakan diatas 16 HP tapi dalam desain
yang kecil ini walaupun berdaya kecil 1 HP jangan diremehkan sebab sebutir granula plastik bila
terlempar ke mata bisa menjadikan cacat buta seumur hidup.
Dudukan dari semua assembling diatas tidak saya sertakan dalam introduction diatas
walaupun nanti memang ada drawingnya dengan alasan anda dapat memodifikasikan sendiri
sesuai selera.
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

MAIN ASSEMBLING
Setelah melihat-lihat sekilas pandang desain mesin regrinder secara orthogonal saya akan
membimbing anda secara sekuensi part pertama mana yang akan anda buat di bengkel. Kembali
pada awal mula drawer membangun / merakit komponen pertama yang akan digambar, begitu
pula saat anda merakit untuk yang pertama kalinya.
Saya punya suggestion parts pertama anda buat adalah sebagai berikut :
1. Rotary crusher.
2. Blades 1 s/d 4.
3. Shaft.
4. Spy / Blind slot 1, 2 dan 3.
5. Nut L dan R.
6. Spacer L dan R.
7. Bearing cover L dan R, dua buah bearing beli di toko.
8. Holder L dan R.
Sampai disini anda coba rakit dahulu, belakangkan parts berikutnya. Tujuannya adalah
sebagai alignment antar parts barangkali ada selisih toleransi saat pengerjaan di bengkel. Bila
perlu ada alignment lakukan dengan pengerjaan sampai toleransi yang diinginkan tercapai.
Apabila dirasa sudah matching lanjutkan pada urutan pengerjaan parts berikut :
9. Deck 2 dan 3.
10. Half shell L dan R.
11. Mesh holder back dan front.
12. 2nd Holder.
13. 2nd blade slider.
14. Deck 1.
15. Mesh.
Seperti yang anda lakukan diatas, rombongan pengerjaan berikutnya dilakukan sesuai
urutan-urutan nomor. Sekali lagi ada baiknya check dan recheck saat parts demi parts telah
selesai dibuat. Apabila prototype yang telah anda bangun sudah jadi dan ditandai atau direvisi
bisa dilanjut ke proses manufacturing dalam sekala fabrikasi misalnya.
Saya ingatkan lagi bahwa drawing yang akan disajikan dalam PDF drawing nanti tidak fixed
dimension. Anda boleh sesuka hati melakukan modifikasi resizing atau lain-lain. Sampai disini
tidak perlu saya sampaikan lagi urutan berikutnya karena sudah jelas untuk parts dibawahnya
atau diatasnya fittingnya mereferensi dua kelompok besar diatas. Dengan cara urutan ini over
under tolerance dapat dihindari dan itulah tujuan saya menjelaskan sebelum annotation
sesungguhnya diberikan kemudian ( Bila anda tertarik untuk membeli e-booknya tentu saja ).
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

CONTOH ANNOTATION / DRAWING DIMENSION
REGRINDER ASSEMBLY MODELS
Yonni Muhazir Production 2013

SYARAT DAN KETENTUAN
1. Produk ini adalah hasil olah desain grafis dari software.
2. Produk ini belum diuji coba secara real.
3. Produk ini didesain dari pengalaman penulis selama duapuluh tahun bekerja sebagai
tenaga teknik di industri plastik ternama yang mempergunakan mesin produksi dari
Germany, Taiwan dan China.
4. Bila anda tertarik oleh produk ini silakan menghubungi administrator di NO HP : 081 803
842 554 XL a/n Bpk. Yonni Muhazir, diutamakan SMS atau e-mail. Produk ini akan saya
hargai nilai nominalnya kemudian via SMS atau penelpon.
5. Mesin real sangat berbahaya dan dapat melukai atau menyebabkab meninggalnya
seseorang. Assembling, commisioning atau operating hanya boleh dilakukan oleh orang
yang sudah berpengalaman electrical dan mechanical dan paham mesin regrind. Sangat
berbahaya untuk anak kecil dan orang yang kurang terlatih. Kami / saya tidak menanggung
kerugian berupa apapun apabila terjadi suatu kecelakaan yang terjadi baik itu electrical
atau mechanicaly.
6. Produk berupa zip PDF file yang akan kami kirimkan pada yang berminat via e-mail setelah
konfirmasi dan sepakat harga via SMS / e-mail.
7. Kami / saya tidak menerima komplain dari peminat setelah e-book terkirim karena
menurut kami / saya melalui introduction ini sudah gamblang bahwa peminat kami anggap
faham dan mengerti uang tidak dapat kembali setelah e-mail drawing attachment diterima.
8. Kami / saya juga tidak akan menuntut pembeli apabila dikemudian hari disebar luaskan /
diperbanyak untuk tujuan komersial atau edukasi.
9. Drawing sebanyak ± 50 Hal. Seperti sample yang terlihat pada hal. 9 diatas.
Malang, 05 July 2013
Yonni Muhazir

Posted in Know How, Solutions | Leave a Comment »

TUTORIAL INJECTION MOULDING MACHINE

Posted by yonni1967 on September 3, 2009

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Telah hadir buku / Tutorial yang anda tunggu-tunggu.

“ Exploring of Injection Moulding Machine “

Buku ini saya susun berdasarkan pengalaman sebagai teknisi mesin Injeksi selama 16 tahun. Kurun waktu tersebut bukanlah waktu yang singkat untuk dapat memahami dan menelanjangi teknologi mesin Injection. Dalam perjalanan tersebut saya sudah banyak disiksa dan kenyang makan asam garam mesin plastik dimana karir saya sebagai teknisi dimulai dengan menangani jenis mesin control relay mekanik sampai control microcomputer.
Tujuan mempublikasikan tutorial ini untuk membantu bagi anda yang baru terjun didunia cetak mencetak produk plastik dengan media mesin Injection disamping sebagai operator, setter atau teknisi lapangan yang baru terjun lantas bingung mencari informasi mesin tersebut.
Sebenarnya banyak informasi yang dapat anda peroleh via Internet namun terpotong-potong dan kurang terdefinisi bila dibandingkan dengan mesin yang anda hadapi. Tak heran karena seperti dunia elektronik, mesin Injection mengalami perkembangan pesat setiap tahunnya. Untuk itulah buku/tutorial ini saya susun secara terstruktur sehingga anda dapat menguasai teknologi mesin Injection secara cepat dan tepat.
Bagaimanakah cara anda mendapatkan buku ini ?. gampang berikut informasinya :

Judul buku : Exploring of Injection Moulding Machine.
Pengarang : Yonni Muhazir.
Bahasa pengantar : Bahasa Indonesia.
Tebal buku : 110 Halaman, Hard Cover.
Statistik buku :21.601 words, Arrial Narrow 12 Point, 1 space.
Kertas : A4, Sidu 70 grams, Cannon printing iP 1980.
Harga : Rp 200.000,-
Dalam kota bebas ongkos kirim.
Dalam propinsi Jatim dikenakan bea kirim Rp 15.000,-
Luar propinsi Jatim dikenakan bea kirim Rp 30.000,-

Cara pemesanan :
Via wessel pos alamatkan ke : Jalan Laksda Adi Sucipto gang 8 no 7 Malang 65125. Buku akan dikirim via paket pos 3 hari setelah uang dicairkan. Kenapa pakai cara tradisional ?. Cara lama lebih disukai karena relatif aman daripada open via transfer bank yang banyak resiko. Bila anda harus melakukan transfer, dapat via BCA yang terlebih dahulu telepon saya kemudian ikuti wizardnya.
Bila ada masalah dalam pengiriman atau lain hal, dapat kontak melalui HP XL 081 803 842 554 a/n : Yonni Muhazir. Atau email ke Yonni_1967@yahoo.co.id .

Mahal amat harga bukunya ?……itu mungkin komentar dalam hati anda………., ..…Sekedar informasi, berikut kalkulasinya :

Beaya cetak 110 halaman x 1000 = Rp 110.000,-
Beaya Hard cover = Rp 30.000,-
Lain lain Rp 15.000,- (beaya transportasi mondar-mandir)

Jadi saya hanya untung tak lebih dari Rp 60.000,- perbukunya dan itu sebagai kompensasi saya sebagai upah lembur mengetik dan lembur ngeprint dan yang terutama harga Informasi yang berharga demi untuk anda. Harga buku sebanding dengan kerja keras saya melekan tiap malam ngetik dan peluh keringat saya mengumpulkan informasi. Anda tidak akan kecewa deh, dari pada anda banyak menghabiskan uang di Internet surfing kesana-kemari. Untuk bahan pertimbangan ( seperti membeli kucing dalam sarung eh..karung dan membuat anda kecewa nanti ), sebelum memesan buku silakan mengintip isinya disini :


Harga dapat berubah-ubah sesuai harga kertas, harga tinta, dan perubahan lain hal. Jadi buruan pesan sekarang juga. Tunggu penerbitan jilid kedua dan ketiga yang tentunya lebih seru dan hot. Dijamin.

Jilid 2 ( Coming soon ) : Hidraulica of Injection Moulding Machine.
Jilid 3 ( Coming soon ) : Getting Start with Injection Moulding Machine.

Maaf tidak melayani pengiriman dalam bentuk soft copy. Semoga bermanfaat bagi semua. Amin……….

Posted in Component Tutorial, Know How, Solutions | Tagged: , , , | Comments Off on TUTORIAL INJECTION MOULDING MACHINE

Multisystems of all Colour Video

Posted by yonni1967 on September 13, 2008

Multisystems of all Colour Video

Information below for student who’s concerning in video colour of the world.

Source information we find from : www.wikipedia.com

What are NTSC, PAL and SECAM?

NTSC (National Television Standards Committee) is a standard used in North America and Japan. It has the ability to display up to 525 lines of resolution. PAL (Phase Alternating Line), a standard used almost everywhere else in the world, has the ability to display 625 lines of resolution. SECAM (Sequential Color Memory) is used sparingly around the world and can be found in France, parts of Greece, Eastern Europe, Russia, Africa and a few other parts of the world. However, any SECAM country can display PAL tapes in full color, but not all PAL countries can display all SECAM tapes in color. Only if they are true SECAM and not MESECAM can those VCR’s display SECAM.

What video standard does my country use?

If you’re in North America, Japan, Korea, the Philippines and parts of South America, you use NTSC. Most other areas of the world use PAL or SECAM. Half of Brazil uses NTSC while the other half uses PAL-M. Argentina, Uruguay and Paraguay use PAL-N. The rest of the world uses mainly PAL. If you’re unsure what your video standard is, contact your local cable or broadcast company. Also, on the back of most videotape is indicating what video standard the tape is. This is a good representation of what your video standard is.

Do I need special types of videotapes to record in different video standards?

No, videotapes are blank. You can get a blank tape and record any video standard onto it.

How do I watch overseas videotapes?

Videotapes come in variety standards, each incompatible with the other. To watch videotapes from overseas that are not the same video standard as your own, you’ll need what is called a multisystem VCR and a multisystem TV, or a Digital Video Standards Converter and VCR, or a VCR with a built-in Converter.

What is a multisystem VCR?

Different areas of the world use different video standards. North America uses NTSC, Europe uses PAL and SECAM, and South America uses PAL-M, PAL-N, PAL and NTSC. Almost every area of the world has a mixture of video standards. Unfortunately, none of these standards are compatible with each other. A multisystem VCR has the ability to play videotapes of different video standards.

Country

Voltage

Frequency

TV System

Afghanistan

220V

50Hz

B/PAL B/SECAM

Albania

220V

50Hz

B.G/PAL

Algeria

127/220V

50Hz

B/PAL

Argentina

220V

50Hz

N/PAL

Australia

240V

50Hz

B.G/PAL

Austria

220V

50Hz

B.G/PAL

Bangladesh

230V

50Hz

B/PAL

Belgium

220V

50Hz

B.H/PAL

Bolivia

110/220V

50/60Hz

N/PAL

Brazil

110/127/220V

60Hz

M/PAL

Brunei

240V

50Hz

B/PAL

Bulgaria

220V

50Hz

D.K/SECAM

Canada

120/230V

60Hz

M/NTSC

Canary Islands

110/220V

50Hz

B.G/PAL

Chile

220V

50Hz

M/NTSC

China

220V

50Hz

D/PAL

Columbia

110/120V

60Hz

M/NTSC

Congo (P. R.)

220V

50Hz

D/SECAM

Costa Rica

120V

60Hz

M/NTSC

Cyprus

240V

50Hz

B.G/PAL

Czechoslovakia

220V

50Hz

D.K/SECAM

Denmark

220V

50Hz

B.G/PAL

Dominican Republic

110V

60Hz

M/NTSC

Ecuador

110V

60Hz

M/NTSC

Egypt

110/220V

50Hz

B/SECAM

El Salvador

110V

60Hz

M/NTSC

Fiji

240V

50Hz

M/NTSC

Finland

220V

50Hz

B.G/PAL

France

127/220V

50Hz

E.L/SECAM

Germany

220V

50Hz

B.G/SECAM/PAL

Gibraltar

240V

50Hz

B.G/PAL

Greece

220V

50Hz

B.G/SECAM

Guam

110V

60Hz

M/NTSC

Guatemala

110/120V

60Hz

M/NTSC

Honduras

110V

60Hz

M/NTSC

Hong Kong

200V

50Hz

I/PAL

Hungary

220V

50Hz

D.K/SECAM

India

230V

50Hz

B/PAL

Indonesia

127/220V

50Hz

B.G/PAL

Iran

220V

50Hz

B/SECAM

Iraq

220V

50Hz

B/SECAM

Ireland

220V

50Hz

AI/PAL

Israel

230V

50Hz

B.G/PAL

Italy

125/220V

50Hz

B.G/PAL

Jamaica

110/220V

50Hz

M/NTSC

Jordan

220V

50Hz

B.G/PAL

Kenya

240V

50Hz

B/PAL

Korea (D. P. R.)

220V

50Hz

D/SECAM

Korea (Rep.)

100/200V

60Hz

M/NTSC

Kuwait

240V

50Hz

B/PAL

Lebanon

110/190V

50Hz

B/SECAM

Liberia

120V

60Hz

B/PAL

Libya

127/230V

50Hz

B/SECAM

Luxembourg

120/220V

50Hz

C/PAL, GL/SECAM

Macao

110/220V

50Hz

I/PAL

Malaysia

240V

50Hz

B/PAL

Mexico

110/220V

50Hz

M/NTSC

Monaco

220V

50Hz

C/PAL, GL/SECAM

Mongolia

220V

50Hz

D/SECAM

Morocco

115/220V

50Hz

B/SECAM

Myanmar

230V

50Hz

M/NTSC

Netherlands

220V

50Hz

B.G/PAL

New Caledonia

220V

50Hz

K1/SECAM

New Zealand

230V

50Hz

B/PAL

Nicaragua

120V

60Hz

M/NTSC

Niger

220V

50Hz

K1/SECAM

Nigeria

230V

50Hz

BG/PAL

Norway

230V

50Hz

B.G/PAL

Oman

220V

50Hz

B.G/PAL

Pakistan

230V

50Hz

B/PAL

Panama

110/120V

60Hz

M/NTSC

Paraguay

220V

50Hz

N/PAL

Peru

220V

60Hz

M/NTSC

Philippines

110/220V

60Hz

M/NTSC

Poland

220V

50Hz

D.K/SECAM

Portugal

220V

50Hz

B.G/PAL

Puerto Rico

120V

60Hz

M/NTSC

Qatar

240V

50Hz

B/PAL

Rumania

220V

50Hz

D.K/PAL

Saudi Arabia

127/220V

50/60Hz

B.G/SECAM, PAL

Singapore

230V

50Hz

B/PAL

South Africa

220/230V

50Hz

I/PAL

Spain

127/220V

50Hz

B.G/PAL

Sri Lanka

230V

50Hz

B/PAL

Sweden

220V

50Hz

B.G/PAL

Switzerland

220V

50Hz

B.G/PAL

Syria

115/200V

50Hz

B/SECAM

Taiwan

110V

60Hz

M/NTSC

Thailand

220V

50Hz

B/PAL

Turkey

220V

50Hz

B/PAL

United Arab Emirates

220V

50Hz

B/PAL

United Kingdom

240V

50Hz

I/PAL

Uruguay

220V

50Hz

N/PAL

USA

120V

60Hz

M/NTSC

C. I. S.

127/220V

50Hz

D.K/SECAM

Venezuela

120V

50/60Hz

N/NTSC

Vietnam

120/220V

50Hz

M/NTSC, D/SECAM

Yemen

230V

50Hz

B/PAL

Yugoslavia

220V

50Hz

B.G/PAL


Posted in Know How | Tagged: | Leave a Comment »

what is the Thermocouple?

Posted by yonni1967 on September 13, 2008

what is the Thermocouple?

In electrical engineering and industry, thermocouples are a widely used type of temperature sensor and can also be used as a means to convert thermal potential difference into electric potential difference.They are cheap and interchangeable, have standard connectors, and can measure a wide range of temperatures. The main limitation is accuracy; System errors of less than one degree Celsius (°C) can be difficult to achieve

History

In 1821, the GermanEstonian physicist Thomas Johann Seebeck discovered that when any conductor (such as a metal) is subjected to a thermal gradient, it will generate a voltage. This is now known as the thermoelectric effect or Seebeck effect. Any attempt to measure this voltage necessarily involves connecting another conductor to the “hot” end. This additional conductor will then also experience the temperature gradient, and develop a voltage of its own which will oppose the original. Fortunately, the magnitude of the effect depends on the metal in use. Using a dissimilar metal to complete the circuit creates a circuit in which the two legs generate different voltages, leaving a small difference in voltage available for measurement. That difference increases with temperature, and can typically be between 1 and 70 microvolts per degree Celsius (µV/°C) for the modern range of available metal combinations. Certain combinations have become popular as industry standards, driven by cost, availability, convenience, melting point, chemical properties, stability, and output. This coupling of two metals gives the thermocouple its name.

Thermocouples measure the temperature difference between two points, not absolute temperature. In traditional applications, one of the junctions—the cold junction—was maintained at a known (reference) temperature, while the other end was attached to a probe.

Having available a known temperature cold junction, while useful for laboratory calibrations, is simply not convenient for most directly connected indicating and control instruments. They incorporate into their circuits an artificial cold junction using some other thermally sensitive device, such as a thermistor or diode, to measure the temperature of the input connections at the instrument, with special care being taken to minimize any temperature gradient between terminals. Hence, the voltage from a known cold junction can be simulated, and the appropriate correction applied. This is known as cold junction compensation.

Additionally, a device can perform cold junction compensation by computation. It can translate device voltages to temperatures by either of two methods. It can use values from look-up tables or approximate using polynomial interpolation.

A thermocouple can produce current, which means it can be used to drive some processes directly, without the need for extra circuitry and power sources. For example, the power from a thermocouple can activate a valve when a temperature difference arises. The electric power generated by a thermocouple is a conversion of the heat energy that one must continuously supply to the hot side of the thermocouple to maintain the electric potential. The flow of heat is necessary because the current flowing through the thermocouple tends to cause the hot side to cool down and the cold side to heat up (the Peltier effect).

Thermocouples can be connected in series with each other to form a thermopile, where all the hot junctions are exposed to the higher temperature and all the cold junctions to a lower temperature. The voltages of the individual thermocouples add up, allowing for a larger voltage and increased power output, thus increasing the sensitivity of the instrumentation. With the radioactive decay of transuranic elements providing a heat source this arrangement has been used to power spacecraft on missions too far from the Sun to utilize solar power.

Thermocouple materials are available in several different metallurgical formulations per type, such as: (listed in decreasing levels of accuracy and cost) Special limits of error, Standard, and Extension grades. Extension grade wire is less costly than dedicated thermocouple junction wire and it’s usually specified for accuracy over a more restricted temperature range. Extension grade wire is used when the point of measurement is farther from the measuring instrument than would be financially viable for standard or special limits materials, and has a very similar thermal coefficient of EMF for a narrow range (usually encompassing ambient). In this case, a standard or special limits wire junction is tied to the extension grade wire outside of the area of temperature measurement for transit to the instrument. Since most modern temperature measuring instruments that utilize thermocouples are electronically buffered to prevent any significant current draw from the thermocouple, the length of the thermocouple or extension wire is irrelevant.

Changes in metallurgy along the length of the thermocouple (such as termination strips or changes in thermocouple type wire) will introduce another thermocouple junction which affects measurement accuracy. Also, in the United States, industry standards are that the thermocouple color code is used for the insulation of the positive lead, and red is the negative lead.

Types…………:

A variety of thermocouples are available, suitable for different measuring applications. They are usually selected based on the temperature range and sensitivity needed. Thermocouples with low sensitivities (B, R, and S types) have correspondingly lower resolutions. Other selection criteria include the inertness of the thermocouple material, and whether or not it is magnetic. The thermocouple types are listed below with the positive electrode first, followed by the negative electrode.

Type K (chromelalumel) is the most commonly used general purpose thermocouple. It is inexpensive and, owing to its popularity, available in a wide variety of probes. They are available in the −200 °C to +1350 °C range. The type K was specified at a time when metallurgy was less advanced than it is today and, consequently, characteristics vary considerably between examples. Another potential problem arises in some situations since one of the constituent metals, nickel, is magnetic. One characteristic of thermocouples made with magnetic material is that they undergo a step change when the magnetic material reaches its Curie point. This occurs for this thermocouple at 354°C. Sensitivity is approximately 41 µV/°C.

Type E

Type E (chromelconstantan) has a high output (68 µV/°C) which makes it well suited to cryogenic use. Additionally, it is non-magnetic.

Type J

Type J (ironconstantan) is less popular than type K due to its limited range (−40 to +750 °C). The main application is with old equipment that cannot accept modern thermocouples. J types cannot be used above 760 °C as an abrupt magnetic transformation causes permanent decalibration. The magnetic properties also prevent use in some applications. Type J thermocouples have a sensitivity of about 50 µV/°C.

Type N

Type N (nicrosilnisil) thermocouples are suitable for use at high temperatures, exceeding 1200 °C, due to their stability and ability to resist high temperature oxidation. Sensitivity is about 39 µV/°C at 900°C, slightly lower than type K. Designed to be an improved type K, it is becoming more popular.

Type B, R, and S

Types B, R, and S thermocouples use platinum or a platinum–rhodium alloy for each conductor. These are among the most stable thermocouples, but have lower sensitivity, approximately 10 µV/°C, than other types. The high cost of these makes them unsuitable for general use. Generally, type B, R, and S thermocouples are used only for high temperature measurements.

Type B thermocouples use a platinum–rhodium alloy for each conductor. One conductor contains 30% rhodium while the other conductor contains 6% rhodium. These thermocouples are suited for use at up to 1800 °C. Type B thermocouples produce the same output at 0 °C and 42 °C, limiting their use below about 50 °C.

Type R thermocouples use a platinum–rhodium alloy containing 13% rhodium for one conductor and pure platinum for the other conductor. Type R thermocouples are used up to 1600 °C.

Type S thermocouples use a platinum–rhodium alloy containing 10% rhodium for one conductor and pure platinum for the other conductor. Like type R, type S thermocouples are used up to 1600 °C. In particular, type S is used as the standard of calibration for the melting point of gold (1064.43 °C).

Type T

Type T (copperconstantan) thermocouples are suited for measurements in the −200 to 350 °C range. Often used as a differential measurement since only copper wire touches the probes. As both conductors are non-magnetic, type T thermocouples are a popular choice for applications such as electrical generators which contain strong magnetic fields. Type T thermocouples have a sensitivity of about 43 µV/°C.

Type C

Type C (tungsten 5% rhenium – tungsten 26% rhenium) thermocouples are suited for measurements in the 0 °C to 2320 °C range. This thermocouple is well-suited for vacuum furnaces at extremely high temperatures and must never be used in the presence of oxygen at temperatures above 260 °C.

Type M

Type M thermocouples use a nickel alloy for each wire. The positive wire contains 18% molybdenum while the negative wire contains 0.8% cobalt.These thermocouples are used in the vacuum furnaces for the same reasons as with type C. Upper temperature is limited to 1400 °C. Though it is a less common type of thermocouple, look-up tables to correlate temperature to EMF (milli-volt output) are available.

Type Chromel-gold/iron

In chromelgold/iron thermocouples, the positive wire is chromel and the negative wire is gold with a small fraction (0.03–0.15 atom percent) of iron. It can be used for cryogenic applications (1.2–300 K and even up to 600 K). Both the sensitivity and the temperature range depends on the iron concentration. The sensitivity is typically around 15 µV/K at low temperatures and the lowest usable temperature varies between 1.2 and 4.2 K.

Thermocouple comparison

The table below describes properties of several different thermocouple types. Within the tolerance columns, T represents the temperature of the hot junction, in degrees Celsius. For example, a thermocouple with a tolerance of ±0.0025×T would have a tolerance of ±2.5 °C at 1000 °C.

TYPE

TEMP. RANGE C (CONTINOUS)

TEMP. RANGE C (SHORT TERM)

TOLERANCE CLASS ONE (C)

TOLERANCE CLASS TWO (C)

K

0 to +1100

180 to +1300

±1.5 between −40 °C and 375 °C
±0.004×T between 375 °C and 1000 °C

±2.5 between −40 °C and 333 °C
±0.0075×T between 333 °C and 1200 °C

J

0 to +700

180 to +800

±1.5 between −40 °C and 375 °C
±0.004×T between 375 °C and 750 °C

±2.5 between −40 °C and 333 °C
±0.0075×T between 333 °C and 750 °C

N

0 to +1100

270 to +1300

±1.5 between −40 °C and 375 °C
±0.004×T between 375 °C and 1000 °C

±2.5 between −40 °C and 333 °C
±0.0075×T between 333 °C and 1200 °C

R

0 to +1600

50 to +1700

±1.0 between 0 °C and 1100 °C
±[1 + 0.003×(T − 1100)] between 1100 °C and 1600 °C

±1.5 between 0 °C and 600 °C
±0.0025×T between 600 °C and 1600 °C

S

0 to 1600

50 to +1750

±1.0 between 0 °C and 1100 °C
±[1 + 0.003×(T − 1100)] between 1100 °C and 1600 °C

±1.5 between 0 °C and 600 °C
±0.0025×T between 600 °C and 1600 °C

B

+200 to +1700

0 to +1820

Not Available

±0.0025×T between 600 °C and 1700 °C

T

185 to +300

250 to +400

±0.5 between −40 °C and 125 °C
±0.004×T between 125 °C and 350 °C

±1.0 between −40 °C and 133 °C
±0.0075×T between 133 °C and 350 °C

E

0 to +800

40 to +900

±1.5 between −40 °C and 375 °C
±0.004×T between 375 °C and 800 °C

±2.5 between −40 °C and 333 °C
±0.0075×T between 333 °C and 900 °C

Chromel/AuFe

272 to +300

n/a

Reproducibility 0.2% of the voltage; each sensor needs individual calibration.

Applications

Thermocouples are most suitable for measuring over a large temperature range, up to 1800 °C. They are less suitable for applications where smaller temperature differences need to be measured with high accuracy, for example the range 0–100 °C with 0.1 °C accuracy. For such applications, thermistors and resistance temperature detectors are more suitable.

Steel industry

Type B, S, R and K thermocouples are used extensively in the steel and iron industries to monitor temperatures and chemistry throughout the steel making process. Disposable, immersible, type S thermocouples are regularly used in the electric arc furnace process to accurately measure the steel’s temperature before tapping. The cooling curve of a small steel sample can be analyzed and used to estimate the carbon content of molten steel.

Heating appliance safety

Many gas-fed heating appliances such as ovens and water heaters make use of a pilot light to ignite the main gas burner as required. If the pilot light becomes extinguished for any reason, there is the potential for un-combusted gas to be released into the surrounding area, thereby creating both risk of fire and a health hazard. To prevent such a danger, some appliances use a thermocouple as a fail-safe control to sense when the pilot light is burning. The tip of the thermocouple is placed in the pilot flame. The resultant voltage, typically around 20 mV, operates the gas supply valve responsible for feeding the pilot. So long as the pilot flame remains lit, the thermocouple remains hot and holds the pilot gas valve open. If the pilot light goes out, the temperature will fall along with a corresponding drop in voltage across the thermocouple leads, removing power from the valve. The valve closes, shutting off the gas and halting this unsafe condition.

Some systems, known as millivolt control systems, extend this concept to the main gas valve as well. Not only does the voltage created by the pilot thermocouple activate the pilot gas valve, it is also routed through a thermostat to power the main gas valve as well. Here, a larger voltage is needed than in a pilot flame safety system described above, and a thermopile is used rather than a single thermocouple. Such a system requires no external source of electricity for its operation and so can operate during a power failure, provided all the related system components allow for this. Note that this excludes common forced air furnaces because external power is required to operate the blower motor, but this feature is especially useful for un-powered convection heaters.

A similar gas shut-off safety mechanism using a thermocouple is sometimes employed to ensure that the main burner ignites within a certain time period, shutting off the main burner gas supply valve should that not happen.

Out of concern for energy wasted by the standing pilot, designers of many newer appliances have switched to an electronically controlled pilot-less ignition, also called intermittent ignition. With no standing pilot flame, there is no risk of gas buildup should the flame go out, so these appliances do not need thermocouple-based safety pilot safety switches. As these designs lose the benefit of operation without a continuous source of electricity, standing pilots are still used in some appliances.

Thermopile radiation sensors

Thermopiles are used for measuring the intensity of incident radiation, typically visible or infrared light, which heats the hot junctions, while the cold junctions are on a heat sink. It is possible to measure radiative intensities of only a few μW/cm2 with commercially available thermopile sensors. For example, some laser power meters are based on such sensors.

Manufacturing

Thermocouples can generally be used in the testing of prototype electrical and mechanical apparatus. For example, switchgear under test for its current carrying capacity may have thermocouples installed and monitored during a heat run test, to confirm that the temperature rise at rated current does not exceed designed limits.

External links :

Retrieved from “http://en.wikipedia.org/wiki/Thermocouple

Categories: Heating, ventilating, and air conditioning | Thermometers | Sensors

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Method of servicing electronic equipment.

Posted by yonni1967 on September 13, 2008

Method of servicing electronic equipment.

The standard tool

The standard tool

By : Yonni Muhazir.

uwiga malang

In the first time if us on servicing electronic goods we think intricate network and make confusedly head. First step is bring damage goods to expert serviceman and buy his services. That is fair…..because improve of repairing electronic goods do not easy as which predicted most societies. Need an education and some practice have to many years to be able handle damage of electronic equipments. Experience of my self was a hard learn electronic skill from kiddy till now. To do that, I invite to all beginners which interest in the field of services electronic with me. I have finished my half age self-study and through by valuable experience. finally blessing by my school in result combination college and experience during many years I have succeeded of giving competent my family life blessing by that skilled.

Commonly…..Opening content of electronic box, initially it is true confuse have to, isn’t it? First question where we have to do start from this?. The visible is intricate of small cable and many path make confuse. Initially me, also that way too. Don’t be doleful, passing a little base lesson of electronics knowledge now will be reveal.

Early mind is feeling vexed, why this equipments can work ?. That just have enough ?. Both second step is human sense of base and enquire in itself : there is a way or systems taking care of this equipments so that like having soul. In this case I think back to nature that if ” something that take care of …” that out of sevice, so…. hence like a missing soul. Then…such as you think, hence the equipments will be “ die.

The “ Death ” of the electronics equipments caused by in-existence of electric current rationing to it. If human being have soul, hence the soul of electronics equipments is the electrics current – existence of it. Commonly trouble electrics current existence sometime indirectly “off” or lose but sometime there is can be chocked. This last situation so-called as “ sick ” cranky pain. This trouble happened caused by direct linking “short circuit” or “ intermitten ” connecting. Sometime also happened caused by component is out of age. Continuous and long-range exceed operation also can destroy this equipments. Also encumbering more exceed capacities causing over heating. The unstableness electricity from the stop contack also cause damage too. Most more because by follow consumer shares of carelessness conducted in this case.

Return to the ” soul ” was mentioned it, so… electrics current have stabilize passing without any disturbance!. Just a little trouble goes there, hence will happened like handicap performance at here!

Kinds of that trouble is :

  • If that trouble at visual, looked into eye was bad picture, trouble example at TV equipment.

  • If that trouble at voice, hence will be heard by hearting voice of our ear, follow the example at sound equipments.

  • If that trouble at digital equipments kinds of numerator machine or computer, hence will be happened chaos arrangement of data and even will be “ hang “ !.

Then…. what method we must do in investigating above electrics current?. We have to assume that electrics current is the same precisely as water current character. Analogy electrics current measure is equal with flow of water where if current in a pipe stuff up hence happened stop current. Equipments to test and analyse electric current is :

  • Avometre. This appliance good for analyzing an electronics existence of voltage, electrics current and resistance. This appliance have to always attend in a technician workbench and is standart technician equipments.

  • Osciloscope. This equipments is a standard laboratory but do not always have to attend in beginner technician workbench.

In real factual of me, I am just only requiring an Avometre, a tool set which compose from : some screwdriver, some kinds of forcepses, good quality soldering iron and that have last for search my earning life… ha..ha…ha…really..!!. and in experience day of my day I look for correct payment of me just rely on that simple equipments, but have succeeded all sort damage of electronics equipments. The secret is to treat electrics current as a real friend. Another secret again is to assuming electronics equipments as divided into some black box and in the handling of that was repair improve in per black box shares. This is important before you correct plunge into world business service of repairing electronic : ad for you have to honesty, at second, having to tough when remembering this world is struggle with a state :” something wrong and have to correct “. Don’t be to easy fulminate, and don’t be easy to stress..!!!!….

Best regards

Yonni

in

Malang town

of

Indonesia

Mailto: yonni_1967@yahoo.co.id or yonni.muhazir@gmail.com

This is Invite to…..: All Malang town Hobbyiest electronics community ( Almahobel ). Hello..? Are you there ? Let us keep community forming such as have there be.. is….

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Optoelectronics

Posted by yonni1967 on September 13, 2008

Aplication notes : Optoelectronics

Optoelectronics is the study and application of electronic devices that interact with light, and thus is usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared. Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers, or instruments that use such devices in their operation. Electro-optics is often erroneously used as a synonym, but is in fact a wider branch of physics that deals with all interactions between light and electric fields, whether or not they form part of an electronic device.

Optoelectronics is based on the quantum mechanical effects of light on semiconducting materials, sometimes in the presence of electric fields.

  • Photoelectric or photovoltaic effect, used in:

    • photodiodes (including solar cells)

    • phototransistors

    • photomultipliers

    • integrated optical circuit (IOC) elements

  • Photoconductivity, used in:

    • photoresistors

    • photoconductive camera tubes

    • charge-coupled imaging devices

  • Stimulated emission, used in:

    • lasers

    • injection laser diodes

  • Lossev effect, or radiative recombination, used in:

    • light-emitting diodes or LED

  • Photoemissivity, used in

    • photoemissive camera tube

Important applications of optoelectronics include:

  • Optocoupler

  • optical fiber communications

Light

Light, or visible light, is electromagnetic radiation of a wavelength that is visible to the human eye (about 400–700 nm). In a scientific context, the word light is sometimes used to refer to the entire electromagnetic spectrum. Light is composed of an elementary particle called a photon.

Three primary properties of light are:

  • Intensity, or brightness;

  • Frequency or wavelength and;

  • Polarization or direction of the wave oscillation.

Light can exhibit properties of both waves and particles. This property is referred to as wave-particle duality. The study of light, known as optics, is an important research area in modern physics.

Speed of light

The speed of light in a vacuum is exactly 299,792,458 m/s (about 186,282.397 miles per second). The speed of light depends upon the medium in which it is traveling, and the speed will be lower in a transparent medium. Although commonly called the “velocity of light”, technically the word velocity is a vector quantity, having both magnitude and direction. Speed refers only to the magnitude of the velocity vector. This fixed definition of the speed of light is a result of the modern attempt, in physics, to define the basic unit of length in terms of the speed of light, rather than defining the speed of light in terms of a length.

Different physicists have attempted to measure the speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century. A good early experiment to measure the speed of light was conducted by Ole Rømer, a Danish physicist, in 1676. Using a telescope, Ole observed the motions of Jupiter and one of its moons, Io. Noting discrepancies in the apparent period of Io’s orbit, Rømer calculated that light takes about 18 minutes to traverse the diameter of Earth’s orbit. Unfortunately, this was not a value that was known at that time. If Ole had known the diameter of the earth’s orbit, he would have calculated a speed of 227,000,000 m/s.

Another, more accurate, measurement of the speed of light was performed in Europe by Hippolyte Fizeau in 1849. Fizeau directed a beam of light at a mirror several kilometers away. A rotating cog wheel was placed in the path of the light beam as it traveled from the source, to the mirror and then returned to its origin. Fizeau found that at a certain rate of rotation, the beam would pass through one gap in the wheel on the way out and the next gap on the way back. Knowing the distance to the mirror, the number of teeth on the wheel, and the rate of rotation, Fizeau was able to calculate the speed of light as 313,000,000 m/s.

Léon Foucault used an experiment which used rotating mirrors to obtain a value of 298,000,000 m/s in 1862. Albert A. Michelson conducted experiments on the speed of light from 1877 until his death in 1931. He refined Foucault’s methods in 1926 using improved rotating mirrors to measure the time it took light to make a round trip from Mt. Wilson to Mt. San Antonio in California. The precise measurements yielded a speed of 299,796,000 m/s.

Refraction

Light in a vacuum propagates at a maximum finite speed, defined above, and denoted by the symbol c. While passing through any other transparent medium, the speed of light slows to some fraction of c. The reduction of the speed of light traveling in a transparent medium is indicated by the refractive index, n, which is defined as:

where v denotes the speed that light travels in the transparent medium.

Note, n = 1 in a vacuum and n > 1 in a transparent medium.

When a beam of light crosses the boundary between a vacuum and another medium, or between two different mediums, the wavelength of the light changes, but the frequency remains constant. If the beam of light is not orthogonal to the boundary, the change in wavelength results in a change in the direction of the beam. This change of direction is known as refraction.

The refraction quality of lenses is frequently used to manipulate light in order to change the apparent size of images. Magnifying glasses, spectacles, contact lenses, microscopes and refracting telescopes are all examples of this manipulation.

Optics

The study of light and the interaction of light and matter is termed optics. The observation and study of optical phenomena such as rainbows and the aurora borealis offer many clues as to the nature of light as well as much enjoyment.

There are many sources of light. The most common light sources are thermal: a body at a given temperature emits a characteristic spectrum of black-body radiation. Examples include sunlight (the radiation emitted by the chromosphere of the Sun at around 6,000 K peaks in the visible region of the electromagnetic spectrum), incandescent light bulbs (which emit only around 10% of their energy as visible light and the remainder as infrared), and glowing solid particles in flames. The peak of the blackbody spectrum is in the infrared for relatively cool objects like human beings. As the temperature increases, the peak shifts to shorter wavelengths, producing first a red glow, then a white one, and finally a blue color as the peak moves out of the visible part of the spectrum and into the ultraviolet. These colors can be seen when metal is heated to “red hot” or “white hot”. The blue color is most commonly seen in a gas flame or a welder’s torch.

Atoms emit and absorb light at characteristic energies. This produces “emission lines” in the spectrum of each atom. Emission can be spontaneous, as in light-emitting diodes, gas discharge lamps (such as neon lamps and neon signs, mercury-vapor lamps, etc.), and flames (light from the hot gas itself—so, for example, sodium in a gas flame emits characteristic yellow light). Emission can also be stimulated, as in a laser or a microwave maser.

Acceleration of a free charged particle, such as an electron, can produce visible radiation: cyclotron radiation, synchrotron radiation, and bremsstrahlung radiation are all examples of this. Particles moving through a medium faster than the speed of light in that medium can produce visible Cherenkov radiation.

Certain chemicals produce visible radiation by chemoluminescence. In living things, this process is called bioluminescence. For example, fireflies produce light by this means, and boats moving through water can disturb plankton which produce a glowing wake.

Certain substances produce light when they are illuminated by more energetic radiation, a process known as fluorescence. This is used in fluorescent lights. Some substances emit light slowly after excitation by more energetic radiation. This is known as phosphorescence.

Phosphorescent materials can also be excited by bombarding them with subatomic particles. Cathodoluminescence is one example of this. This mechanism is used in cathode ray tube televisions.

Certain other mechanisms can produce light:

  • scintillation

  • electroluminescence

  • sonoluminescence

  • triboluminescence

  • Cherenkov radiation

When the concept of light is intended to include very-high-energy photons (gamma rays), additional generation mechanisms include:

  • radioactive decay

  • particle–antiparticle annihilation

Optical theory

The Muslim scientist Ibn al-Haytham (c. 965-1040), known as Alhacen in the West, in his Book of Optics, developed a broad theory that explained vision, using geometry and anatomy, which stated that each point on an illuminated area or object radiates light rays in every direction, but that only one ray from each point, which strikes the eye perpendicularly, can be seen. The other rays strike at different angles and are not seen. He described the pinhole camera and invented the camera obscura, which produces an inverted image, and used it as an example to support his argument.This contradicted Ptolemy’s theory of vision that objects are seen by rays of light emanating from the eyes. Alhacen held light rays to be streams of minute particles that travelled at a finite speed. He improved Ptolemy’s theory of the refraction of light, and went on to discover the laws of refraction.

He also carried out the first experiments on the dispersion of light into its constituent colors. His major work Kitab al-Manazir was translated into Latin in the Middle Ages, as well his book dealing with the colors of sunset. He dealt at length with the theory of various physical phenomena like shadows, eclipses, the rainbow. He also attempted to explain binocular vision, and gave a correct explanation of the apparent increase in size of the sun and the moon when near the horizon. Because of his extensive research on optics, Al-Haytham is considered the father of modern optics.

Al-Haytham also correctly argued that we see objects because the sun’s rays of light, which he believed to be streams of tiny particles travelling in straight lines, are reflected from objects into our eyes. He understood that light must travel at a large but finite velocity, and that refraction is caused by the velocity being different in different substances. He also studied spherical and parabolic mirrors, and understood how refraction by a lens will allow images to be focused and magnification to take place. He understood mathematically why a spherical mirror produces aberration.

Wave theory

In the 1660s, Robert Hooke published a wave theory of light. Christiaan Huygens worked out his own wave theory of light in 1678, and published it in his Treatise on light in 1690. He proposed that light was emitted in all directions as a series of waves in a medium called the Luminiferous ether. As waves are not affected by gravity, it was assumed that they slowed down upon entering a denser medium.

Thomas Young’s sketch of the two-slit experiment showing the diffraction of light. Young’s experiments supported the theory that light consists of waves.

The wave theory predicted that light waves could interfere with each other like sound waves (as noted around 1800 by Thomas Young), and that light could be polarized. Young showed by means of a diffraction experiment that light behaved as waves. He also proposed that different colors were caused by different wavelengths of light, and explained color vision in terms of three-colored receptors in the eye.

Another supporter of the wave theory was Leonhard Euler. He argued in Nova theoria lucis et colorum (1746) that diffraction could more easily be explained by a wave theory.

Later, Augustin-Jean Fresnel independently worked out his own wave theory of light, and presented it to the Académie des Sciences in 1817. Simeon Denis Poisson added to Fresnel’s mathematical work to produce a convincing argument in favour of the wave theory, helping to overturn Newton’s corpuscular theory.

The weakness of the wave theory was that light waves, like sound waves, would need a medium for transmission. A hypothetical substance called the luminiferous aether was proposed, but its existence was cast into strong doubt in the late nineteenth century by the Michelson-Morley experiment.

Newton’s corpuscular theory implied that light would travel faster in a denser medium, while the wave theory of Huygens and others implied the opposite. At that time, the speed of light could not be measured accurately enough to decide which theory was correct. The first to make a sufficiently accurate measurement was Léon Foucault, in 1850. His result supported the wave theory, and the classical particle theory was finally abandoned.

Electromagnetic theory

A linearly-polarized light wave frozen in time and showing the two oscillating components of light; an electric field and a magnetic field perpendicular to each other and to the direction of motion (a transverse wave).

In 1845, Michael Faraday discovered that the angle of polarization of a beam of light as it passed through a polarizing material could be altered by a magnetic field, an effect now known as Faraday rotation. This was the first evidence that light was related to electromagnetism. Faraday proposed in 1847 that light was a high-frequency electromagnetic vibration, which could propagate even in the absence of a medium such as the ether.

Faraday’s work inspired James Clerk Maxwell to study electromagnetic radiation and light. Maxwell discovered that self-propagating electromagnetic waves would travel through space at a constant speed, which happened to be equal to the previously measured speed of light. From this, Maxwell concluded that light was a form of electromagnetic radiation: he first stated this result in 1862 in On Physical Lines of Force. In 1873, he published A Treatise on Electricity and Magnetism, which contained a full mathematical description of the behaviour of electric and magnetic fields, still known as Maxwell’s equations. Soon after, Heinrich Hertz confirmed Maxwell’s theory experimentally by generating and detecting radio waves in the laboratory, and demonstrating that these waves behaved exactly like visible light, exhibiting properties such as reflection, refraction, diffraction, and interference. Maxwell’s theory and Hertz’s experiments led directly to the development of modern radio, radar, television, electromagnetic imaging, and wireless communications.

Light-emitting diode

LED Image

LED Image

A light-emitting diode (LED) is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction, as in the common LED circuit. This effect is a form of electroluminescence.

An LED is usually a small area source, often with extra optics added to the chip that shapes its radiation pattern. LED’s are often used as small indicator lights on electronic devices and increasingly in higher power applications such as flashlights and area lighting. The color of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible, or near-ultraviolet. An LED can be used as a regular household light source.

LED technology

Like a normal diode, an LED consists of a chip of semiconducting material impregnated, or doped, with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.

The wavelength of the light emitted, and therefore its color, depends on the band gap energy of the materials forming the p-n junction. In silicon or germanium diodes, the electrons and holes recombine by a non-radiative transition which produces no optical emission, because these are indirect band gap materials. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.

LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors.

LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface. P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate. Substrates that are transparent to the emitted wavelength, and backed by a reflective layer, increase the LED efficiency. The refractive index of the package material should match the index of the semiconductor, otherwise the produced light gets partially reflected back into the semiconductor, where it may be absorbed and turned into additional heat, thus lowering the efficiency. This type of reflection also occurs at the surface of the package if the LED is coupled to a medium with a different refractive index such as a glass fiber or air. The refractive index of most LED semiconductors is quite high, so in almost all cases the LED is coupled into a much lower-index medium. The large index difference makes the reflection quite substantial (per the Fresnel coefficients), and this is usually one of the dominant causes of LED inefficiency. Often more than half of the emitted light is reflected back at the LED-package and package-air interfaces. The reflection is most commonly reduced by using a dome-shaped (half-sphere) package with the diode in the center so that the outgoing light rays strike the surface perpendicularly, at which angle the reflection is minimized. An anti-reflection coating may be added as well. The package may be cheap plastic, which may be colored, but this is only for cosmetic reasons or to improve the contrast ratio; the color of the packaging does not substantially affect the color of the light emitted. Other strategies for reducing the impact of the interface reflections include designing the LED to reabsorb and reemit the reflected light (called photon recycling) and manipulating the microscopic structure of the surface to reduce the reflectance, either by introducing random roughness or by creating programmed moth eye surface patterns.

Conventional LEDs are made from a variety of inorganic semiconductor materials, producing the following colors:

  • Aluminium gallium arsenide (AlGaAs) — red and infrared

  • Aluminium gallium phosphide (AlGaP) — green

  • Aluminium gallium indium phosphide (AlGaInP) — high-brightness orange-red, orange, yellow, and green

  • Gallium arsenide phosphide (GaAsP) — red, orange-red, orange, and yellow

  • Gallium phosphide (GaP) — red, yellow and green

  • Gallium nitride (GaN) — green, pure green (or emerald green), and blue also white (if it has an AlGaN Quantum Barrier)

  • Indium gallium nitride (InGaN) — 450nm – 470nm — near ultraviolet, bluish-green and blue

  • Silicon carbide (SiC) as substrate — blue

  • Silicon (Si) as substrate — blue (under development)

  • Sapphire (Al2O3) as substrate — blue

  • Zinc selenide (ZnSe) — blue

  • Diamond (C) — ultraviolet

  • Aluminium nitride (AlN), aluminium gallium nitride (AlGaN), aluminium gallium indium nitride (AlGaInN) — near to far ultraviolet (down to 210 nm)

With this wide variety of colors, arrays of multicolor LEDs can be designed to produce unconventional color patterns.

Ultraviolet and blue LEDs

Ultraviolet GaN LEDs.

Blue LEDs are based on the wide band gap semiconductors GaN (gallium nitride) and InGaN (indium gallium nitride). They can be added to existing red and green LEDs to produce the impression of white light, though white LEDs today rarely use this principle.

The first blue LEDs were made in 1971 by Jacques Pankove (inventor of the gallium nitride LED) at RCA Laboratories. However, these devices were too feeble to be of much practical use. In the late 1980s, key breakthroughs in GaN epitaxial growth and p-type doping by Akasaki and Amano (Nagoya, Japan) ushered in the modern era of GaN-based optoelectronic devices. Building upon this foundation, in 1993 high brightness blue LEDs were demonstrated through the work of Shuji Nakamura at Nichia Corporation.

By the late 1990s, blue LEDs had become widely available. They have an active region consisting of one or more InGaN quantum wells sandwiched between thicker layers of GaN, called cladding layers. By varying the relative InN-GaN fraction in the InGaN quantum wells, the light emission can be varied from violet to amber. AlGaN aluminium gallium nitride of varying AlN fraction can be used to manufacture the cladding and quantum well layers for ultraviolet LEDs, but these devices have not yet reached the level of efficiency and technological maturity of the InGaN-GaN blue/green devices. If the active quantum well layers are GaN, as opposed to alloyed InGaN or AlGaN, the device will emit near-ultraviolet light with wavelengths around 350–370 nm. Green LEDs manufactured from the InGaN-GaN system are far more efficient and brighter than green LEDs produced with non-nitride material systems.

With aluminium containing nitrides, most often AlGaN and AlGaInN, even shorter wavelengths are achievable. Ultraviolet LEDs are becoming available on the market, in a range of wavelengths. Near-UV emitters at wavelengths around 375–395 nm are already cheap, common to encounter e.g., as black light lamp replacements for inspection of anti-counterfeiting UV watermarks in some documents and paper currencies. Shorter wavelength diodes, while substantially more expensive, are commercially available for wavelengths down to 247 nm. As the photosensitivity of microorganisms approximately matches the absorption spectrum of DNA, with peak at about 260 nm, UV LEDs emitting at 250–270 nm are prospective for disinfecting devices.

Wavelengths down to 210 nm were obtained in laboratories using aluminium nitride.

While not actually an LED as such, an ordinary NPN bipolar transistor will emit violet light if its emitter-base junction is subjected to non-destructive reverse breakdown. This is easy to demonstrate by filing the top off a metal-can transistor (BC107, 2N2222 or similar) and biasing it well above emitter-base breakdown (≥ 20 V) via a current limiting resistor.

White LEDs

A combination of red, green and blue LEDs can produce the impression of white light, though white LEDs today rarely use this principle. Most “white” LEDs in production today are modified blue LEDs: GaN-based, InGaN-active-layer LEDs emit blue light of wavelengths between 450 nm and 470 nm. This InGaN-GaN structure is covered with a yellowish phosphor coating usually made of cerium-doped yttrium aluminum garnet (Ce3+:YAG) crystals which have been powdered and bound in a type of viscous adhesive. The LED chip emits blue light, part of which is efficiently converted to a broad spectrum centered at about 580 nm (yellow) by the Ce3+:YAG. Since yellow light stimulates the red and green receptors of the eye, the resulting mix of blue and yellow light gives the appearance of white, the resulting shade often called “lunar white”. This approach was developed by Nichia and has been used since 1996 for the manufacture of white LEDs.

The pale yellow emission of the Ce3+:YAG can be tuned by substituting the cerium with other rare earth elements such as terbium and gadolinium and can even be further adjusted by substituting some or all of the aluminum in the YAG with gallium. Due to the spectral characteristics of the diode, the red and green colors of objects in its blue yellow light are not as vivid as in broad-spectrum light. Manufacturing variations and varying thicknesses in the phosphor make the LEDs produce light with different color temperatures, from warm yellowish to cold bluish; the LEDs have to be sorted during manufacture by their actual characteristics. Philips Lumileds patented conformal coating process addresses the issue of varying phosphor thickness, giving the white LEDs a more consistent spectrum of white light.

Spectrum of a “white” LED clearly showing blue light which is directly emitted by the GaN-based LED (peak at about 465 nanometers) and the more broadband stokes shifted light emitted by the Ce3+:YAG phosphor which extends from around 500 to 700 nanometers.

White LEDs can also be made by coating near ultraviolet (NUV) emitting LEDs with a mixture of high efficiency europium-based red and blue emitting phosphors plus green emitting copper and aluminum doped zinc sulfide (ZnS:Cu, Al). This is a method analogous to the way fluorescent lamps work. However the ultraviolet light causes photodegradation to the epoxy resin and many other materials used in LED packaging, causing manufacturing challenges and shorter lifetimes. This method is less efficient than the blue LED with YAG:Ce phosphor, as the Stokes shift is larger and more energy is therefore converted to heat, but yields light with better spectral characteristics, which render color better. Due to the higher radiative output of the ultraviolet LEDs than of the blue ones, both approaches offer comparable brightness.

The newest method used to produce white light LEDs uses no phosphors at all and is based on homoepitaxially grown zinc selenide (ZnSe) on a ZnSe substrate which simultaneously emits blue light from its active region and yellow light from the substrate.

A new technique developed by Michael Bowers, a graduate student at Vanderbilt University in Nashville, involves coating a blue LED with quantum dots that glow white in response to the blue light from the LED. This technique produces a warm, yellowish-white light similar to that produced by incandescent bulbs.

Organic light-emitting diodes (OLEDs)

Combined spectral curves for blue, yellow-green, and high brightness red solid-state semiconductor LEDs. FWHM spectral bandwidth is approximately 24–27 nanometres for all three colors.

If the emitting layer material of an LED is an organic compound, it is known as an Organic Light Emitting Diode (OLED). To function as a semiconductor, the organic emitting material must have conjugated pi bonds. The emitting material can be a small organic molecule in a crystalline phase, or a polymer. Polymer materials can be flexible; such LEDs are known as PLEDs or FLEDs.

Compared with regular LEDs, OLEDs are lighter, and polymer LEDs can have the added benefit of being flexible. Some possible future applications of OLEDs could be:

  • Inexpensive, flexible displays

  • Light sources

  • Wall decorations

  • Luminous cloth

OLEDs have been used to produce visual displays for portable electronic devices such as cellphones, digital cameras, and MP3 players. Larger displays have been demonstrated, but their life expectancy is still far too short (<1,000 hours) to be practical.

Operational parameters and efficiency

Most typical LEDs are designed to operate with no more than 30–60 milliwatts of electrical power. Around 1999, Philips Lumileds introduced power LEDs capable of continuous use at one watt. These LEDs used much larger semiconductor die sizes to handle the large power inputs. Also, the semiconductor dies were mounted onto metal slugs to allow for heat removal from the LED die.

One of the key advantages of LED-based lighting is its high efficiency, as measured by its light output per unit power input. White LEDs quickly matched and overtook the efficiency of standard incandescent lighting systems. In 2002, Lumileds made five-watt LEDs available with a luminous efficacy of 18–22 lumens per watt. For comparison, a conventional 60–100 watt incandescent lightbulb produces around 15 lumens/watt, and standard fluorescent lights produce up to 100 lumens/watt. (The luminous efficacy article discusses these comparisons in more detail.)

In September 2003, a new type of blue LED was demonstrated by the company Cree, Inc. to provide 24 mW at 20 mA. This produced a commercially packaged white light giving 65 lumens per watt at 20 mA, becoming the brightest white LED commercially available at the time, and more than four times as efficient as standard incandescents. In 2006 they demonstrated a prototype with a record white LED luminous efficacy of 131 lm/W at 20 mA. Also, Seoul Semiconductor has plans for 135 lm/W by 2007 and 145 lm/W by 2008, which would be approaching an order of magnitude improvement over standard incandescents and better even than standard fluorescents. Nichia Corp. has developed a white light LED with luminous efficacy of 150 lm/W at a forward current of 20 mA.

It should be noted that high-power (≥ 1 Watt) LEDs are necessary for practical general lighting applications. Typical operating currents for these devices begin at 350 mA. The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA).

Today, OLEDs operate at substantially lower efficiency than inorganic (crystalline) LEDs. The best luminous efficacy of an OLED so far is about 10% of the theoretical maximum of 683, or about 68 lm/W. These claim to be much cheaper to fabricate than inorganic LEDs, and large arrays of them can be deposited on a screen using simple printing methods to create a color graphical display.

Considerations in use

Unlike incandescent light bulbs, which light up regardless of the electrical polarity, LEDs will only light with correct electrical polarity. When the voltage across the p-n junction is in the correct direction, a significant current flows and the device is said to be forward-biased. If the voltage is of the wrong polarity, the device is said to be reverse biased, very little current flows, and no light is emitted. Some LEDs can be operated on an alternating current voltage, but they will only light with positive voltage, causing the LED to turn on and off at the frequency of the AC supply.

While the only 100% accurate way to determine the polarity of an LED is to examine its datasheet, these methods are usually reliable:

sign:

+

terminal:

anode (A)

cathode (K)

leads:

long

short

exterior:

round

flat

interior:

small

large

wiring:

red

black

Less reliable methods of determining polarity are:

sign:

+

marking:

none

stripe

pin:

1

2

PCB:

round

square

While it is not an officially reliable method, it is almost universally true that the cup that holds the LED die corresponds to the cathode. It is strongly recommended to apply a safe voltage and observe the illumination as a test regardless of what method is used to determine the polarity.

Because the voltage versus current characteristics of an LED are much like any diode (that is, current approximately an exponential function of voltage), a small voltage change results in a huge change in current. Added to deviations in the process this means that a voltage source may barely make one LED light while taking another of the same type beyond its maximum ratings and potentially destroying it.

Since the voltage is logarithmically related to the current it can be considered to remain largely constant over the LEDs operating range. Thus the power can be considered to be almost proportional to the current. In order to keep power nearly constant with variations in supply and LED characteristics, the power supply should be a “current source”, that is, it should supply an almost constant current. If high efficiency is not required (e.g., in most indicator applications), an approximation to a current source made by connecting the LED in series with a current limiting resistor to a constant voltage source is generally used.

Most LEDs have low reverse breakdown voltage ratings, so they will also be damaged by an applied reverse voltage of more than a few volts. Since some manufacturers don’t follow the indicator standards above, if possible the data sheet should be consulted before hooking up an LED, or the LED may be tested in series with a resistor on a sufficiently low voltage supply to avoid the reverse breakdown. If it is desired to drive an LED directly from an AC supply of more than the reverse breakdown voltage then it may be protected by placing a diode (or another LED) in inverse parallel.

LEDs can be purchased with built in series resistors. These can save PCB space and are especially useful when building prototypes or populating a PCB in a way other than its designers intended. However the resistor value is set at the time of manufacture, removing one of the key methods of setting the LED’s intensity. To increase efficiency (or to allow intensity control without the complexity of a DAC), the power may be applied periodically or intermittently; so long as the flicker rate is greater than the human flicker fusion threshold, the LED will appear to be continuously lit.

Provided there is sufficient voltage available, multiple LEDs can be connected in series with a single current limiting resistor. Parallel operation is generally problematic. The LEDs have to be of the same type in order to have a similar forward voltage. Even then, variations in the manufacturing process can make the odds of satisfactory operation low.

Bicolor LED units contain two diodes, one in each direction (that is, two diodes in inverse parallel) and each a different color (typically red and green), allowing two-color operation or a range of apparent colors to be created by altering the percentage of time the voltage is in each polarity. Other LED units contain two or more diodes (of different colors) arranged in either a common anode or common cathode configuration. These can be driven to different colors without reversing the polarity, however, more than two electrodes (leads) are required.

LEDs are usually constantly illuminated when a current passes through them, but flashing LEDs are also available. Flashing LEDs resemble standard LEDs but they contain an integrated multivibrator circuit inside which causes the LED to flash with a typical period of one second. This type of LED comes most commonly as red, yellow, or green. Most flashing LEDs emit light of a single wavelength, but multicolored flashing LEDs are available too.

Generally, for newer common standard LEDs in 3 mm or 5 mm packages, the following forward DC potential differences are typically measured. The forward potential difference depending on the LED’s chemistry, temperature, and on the current (values here are for approx. 20 milliamperes, a commonly found maximum value).

Color

Potential Difference

Infrared

1.6 V

Red

1.8 V to 2.1 V

Orange

2.2 V

Yellow

2.4 V

Green

2.6 V

Blue

3.0 V to 3.5 V

White

3.0 V to 3.5 V

Ultraviolet

3.5 V

Many LEDs are rated at 5 V maximum reverse voltage.

LEDs also behave as photocells, and will generate a current depending on the ambient light. They are not efficient as photocells, and will only produce a few microamps, but will put out a surprising voltage level, as much as 2 or 3 volts. This is enough to operate an amplifier or CMOS logic gate. This effect can be used to make an inexpensive light sensor, for example to decide when to turn on an LED illuminator.

Advantages of using LEDs

  • LEDs produce more light per watt than do incandescent bulbs; this is useful in battery powered or energy-saving devices.

  • LEDs can emit light of an intended color without the use of color filters that traditional lighting methods require. This is more efficient and can lower initial costs.

  • The solid package of an LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner.

  • When used in applications where dimming is required, LEDs do not change their color tint as the current passing through them is lowered, unlike incandescent lamps, which turn yellow.

  • LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently, or HID lamps that require a long time before restarting.

  • LEDs, being solid state components, are difficult to damage with external shock. Fluorescent and incandescent bulbs are easily broken if dropped on the ground.

  • LEDs can have a relatively long useful life. One report estimates 35,000 to 50,000 hours of useful life, though time to complete failure may be longer. Fluorescent tubes typically are rated at about 30,000 hours, and incandescent light bulbs at 1,000–2,000 hours.[citation needed]

  • LEDs mostly fail by dimming over time, rather than the abrupt burn-out of incandescent bulbs.

  • LEDs light up very quickly. A typical red indicator LED will achieve full brightness in microseconds; LEDs used in communications devices can have even faster response times.

  • LEDs can be very small and are easily populated onto printed circuit boards.

  • LEDs do not contain mercury, while compact fluorescent lamps do.

LEDs are produced in an array of shapes and sizes. The 5 mm cylindrical package (red, fifth from the left) is the most common, estimated at 80% of world production. The color of the plastic lens is often the same as the actual color of light emitted, but not always. For instance, purple plastic is often used for infrared LEDs, and most blue devices have clear housings. There are also LEDs in extremely tiny packages, such as those found on blinkies (not shown).

Disadvantages of using LEDs

  • LEDs are currently more expensive, price per lumen, on an initial capital cost basis, than more conventional lighting technologies. The additional expense partially stems from the relatively low lumen output and the drive circuitry and power supplies needed. However, when considering the total cost of ownership (including energy and maintenance costs), LEDs far surpass incandescent or halogen sources and begin to threaten compact fluorescent lamps. In December 2007, scientist at Glasgow University claimed to have found a way to make Light Emitting Diodes brighter and use less power than energy efficient light bulbs currently on the market by imprinting the holes into billions of LEDs in a new and cost effective method using a process known as nanoimprint lithography.

  • LED performance largely depends on the ambient temperature of the operating environment. Driving an LED hard in high ambient temperatures may result in overheating of the LED package, eventually leading to device failure. Adequate heat-sinking is required to maintain long life. This is especially important when considering automotive, medical, and military applications where the device must operate over a large range of temperatures, and is required to have a low failure rate.

  • LEDs must be supplied with the correct current. This can involve shunt resistors or regulated power supplies.

  • The spectrum of some white LEDs differs significantly from a black body radiator, such as the sun or an incandescent light. The spike at 460 nm and dip at 500 nm can cause the color of objects to be perceived differently under LED illumination than sunlight or incandescent sources, due to metamerism. However, it should be noted that color rendering properties of common fluorescent lamps are often inferior to what is now available in state-of-art white LEDs.

  • LEDs do not approximate a “point source” of light, so cannot be used in applications that need a sharply directive and collimated beam. LEDs are not capable of providing directivity below a few degrees. In such cases LASERs (or amplified spontaneous emission devices) may be a better option.

  • There is increasing concern that blue LEDs and white LEDs are now capable of exceeding safe limits of the so-called blue-light hazard as defined in eye safety specifications such as ANSI/IESNA RP-27.1-05: Recommended Practice for Photobiological Safety for Lamp and Lamp Systems.

Types

There are 3 main types of LEDs: miniature LEDs, alphanumeric LEDs, and lighting LEDs.

Miniature LEDs

These are mostly single die LEDs used as indicators, and come in various size packages:

  • surface mount

  • 2mm

  • 3mm

  • 5mm

  • Other sizes are also available, but less common.

There are 3 main categories of miniature single die LEDs:

  • Low current – typically rated for 2mA at around 2v (apx 4mW consumption).

  • Standard – 20mA LEDs at around 2v (apx 40mW) for red, orange, yellow & green, and 20mA at 4-5v (apx 0.1W) for blue, violet and white.

  • Ultra high output – 20mA at apx 2v or 4-5v, designed for viewing in direct sunlight. These have enough light output to light a very small object, or may be used in low output torches.

Multicolour LEDs

Bicolour LEDs contain 2 dice of different colours connected back to back, and can produce any of 3 colours. Current flow in one direction produces one colour, current in the other direction produces the other colour, and bidirectional current produces both colours mixed together.

Tricolour LEDs contain 3 dice. Often these are RGB dice, but not always. These LEDs can be driven to produce a wider range of colours, and in the case of RBG LEDS nearly the whole visible spectrum of colours.

5v & 12v LEDs

These are miniature LEDs incorporating a series resistor, and may be connected directly to 5v or 12v.

Flashing LEDs

These miniature LEDs flash when connected to 5v or 12v. Used as attention seeking indicators where it is desired to avoid the complexity of external electronics.

Alphanumeric LEDs

LED displays are available in 7 segment and starburst format. 7 segment displays handle all numbers and a limited set of letters. Starburst displays can display all letters.

7 segment LED displays were in widespread use in the 1970s and 1980s, but increasing use of LCD displays, with their lower power consumption and greater display flexibility, has reduced the popularity of numeric and alphanumeric LED displays.

Lighting LEDs

LED lamps (also called LED bars or Illuminators) are usually clusters of LEDs in a suitable housing. They come in different shapes, among them the light bulb shape with a large E27 Edison screw and MR16 shape with a bi-pin base. Other models might have a small Edison E14 fitting, GU5.3 (Bipin cap) or GU10 (bayonet socket). This includes low voltage (typically 12 V halogen-like) varieties and replacements for regular AC mains (120-240 V AC) lighting. Currently the latter are less widely available but this is changing rapidly.

LED applications

  1. LED panel light source used in an experiment on plant growth. The findings of such experiments may be used to grow food in space on long duration missions.

  2. Light sources for machine vision systems.

  3. An LED destination display on a bus. Note how the camera has had difficulty catching all the LEDs.

  4. Old calculator LED display.

  5. Flashlights and lanterns that utilise white LEDs are becoming increasingly popular due to their durability and longer battery life.

  6. Single high-brightness LED with a glass lens creates a bright carrier beam that can stream DVD-quality video over considerable distances. The device, RONJA, can be built very simply by enthusiasts.

  7. LED lights on an Audi S6

List of LED applications

Some of these applications are further elaborated upon in the following text.

  • Streetlights

  • Large scale video displays

  • Architectural lighting

  • Status indicators on all sorts of equipment

  • Traffic lights and signals

  • Light source for machine vision systems, requiring bright, focused, homogeneous and possibly strobed illumination.

  • Exit signs

  • Motorcycle and Bicycle lights

  • Toys and recreational sporting goods, such as the Flashflight

  • Railroad crossing signals

  • Continuity indicators

  • Flashlights, including some mechanically powered models.

  • Emergency vehicle lighting

  • Elevator Push Button Lighting

  • Thin, lightweight message displays at airports and railway stations and as destination displays for trains, buses, trams and ferries.

  • Red or yellow LEDs are used in indicator and alphanumeric displays in environments where night vision must be retained: aircraft cockpits, submarine and ship bridges, astronomy observatories, and in the field, e.g. night time animal watching and military field use.

  • Red, yellow, green, and blue LEDs can be used for model railroading applications

  • Remote controls, such as for TVs and VCRs, often use infrared LEDs.

  • The Nintendo Wii’s sensor bar uses infrared LEDs.

  • In optical fiber and Free Space Optics communications.

  • In dot matrix arrangements for displaying messages.

  • Glowlights, as a more expensive but longer lasting and reusable alternative to Glowsticks.

  • Grow lights composed of LEDs are more efficient, both because LEDs produce more lumens per watt than other alternatives, and also because they can be tuned to the specific wavelengths plants can make the most use of.[citation needed]

  • Movement sensors, for example in optical computer mice

  • Because of their long life and fast switching times, LEDs have been used for automotive high-mounted brake lights and truck and bus brake lights and turn signals for some time, but many high-end vehicles are now starting to use LEDs for their entire rear light clusters. Besides the gain in reliability, this has styling advantages because LEDs are capable of forming much thinner lights than incandescent lamps with parabolic reflectors. The significant improvement in the time taken to light up (perhaps 0.5s faster than an incandescent bulb) improves safety by giving drivers more time to react. It has been reported that at normal highway speeds this equals one car length increased reaction time for the car behind. White LED headlamps are beginning to make an appearance.

  • Backlighting for LCD televisions and displays. The availability of LEDs in specific colors (RGB) enables a full-spectrum light source which expands the color gamut by as much as 45%.

  • New stage lighting equipment is being developed with LED sources in primary red-green-blue arrangements.

  • Lumalive, a photonic textile

  • LED-based Christmas lights have been available since 2002, but are only now beginning to gain in popularity and acceptance due to their higher initial purchase cost when compared to similar incandescent-based Christmas lights. For example, as of 2006, a set of 50 incandescent lights might cost US$2, while a similar set of 50 LED lights might cost US$10. The purchase cost can be even higher for single-color sets of LED lights with rare or recently-introduced colors, such as purple, pink or white. Regardless of the higher initial purchase price, the total cost of ownership for LED Christmas lights would eventually be lower than the TCO for similar incandescent Christmas lights[citation needed] since an LED requires much less power to output the same amount of light as a similar incandescent bulb. More to the point, LEDs have practically unlimited life and are hard-wired rather than using unreliable sockets as do replaceable bulbs. So a set of LED lights can be expected to outlive many incandescent sets, and without any maintenance.

  • LED phototherapy for acne using blue or red LEDs has been proven to significantly reduce acne over a 3 month period.[citation needed]

  • As a medium quality voltage reference in electronic circuits. The forward voltage drop (e.g., about 1.7 V for a normal red LED) can be used instead of a Zener diode in low-voltage regulators. Although LED forward voltage is much more current-dependent than a good Zener, Zener diodes are not available below voltages of about 3 V.

  • Some flatbed scanners use an array of red, green, and blue LEDs rather than the typical cold-cathode fluorescent lamp as the light source. Having independent control of three illuminant colors allows the scanner to calibrate itself for more accurate color balance, and there is no need for warm-up.

  • Computers, for hard drive activity and power on. Some custom computers feature LED accent lighting to draw attention to a given component. Many computer manufactuers use LEDs to tell the user its current state. One example would be the Mac, which tells its user when it is asleep by fading the LED activity lights in and out, in and out.

  • Light bulbs

  • Lanterns

Optoisolators and optocouplers

Optocoupler schematic showing LED and phototransistorAn LED may be combined with a photodiode or phototransistor in a single electronic device to provide a signal path with electrical isolation between two circuits. An optoisolator will have typical breakdown voltages between the input and output circuits of typically 500 to 3000 volts. This is especially useful in medical equipment where the signals from a low voltage sensor circuit (usually battery powered) in contact with a living organism must be electrically isolated from any possible electrical failure in a recording or montoring device operating at potentially dangerous voltages. An optoisolator also allows information to be transferred between circuits not sharing a common ground potential. An optocoupler may not have such high breakdown voltages and may even share a ground between input and output, but both types are useful in preventing electrical noise, particularly common mode electrical noise, on a sensor circuit from being transferred to the receiving circuit (where it may adversly affect the operation or durability of various components) and/or transferring a noisy signal. Optoisolators are also used in the feedback circuit of a DC to DC converter, allowing power to be transferred while retaining electrical isolation between the input and output.

Indicator LEDs

Miniature indicator LEDs are normally driven from low voltage DC via a current limiting resistor. Currents of 2mA, 10mA and 20mA are common. Some low current indicators are only rated to 2mA, and should not be driven at higher current.

Sub-mA indicators may be made by driving ultrabright LEDs at very low current. Efficacy tends to reduce at low currents, but indicators running on 100uA are still practical. The cost of ultrabrights is higher than 2mA indicator LEDs.

LEDs have a low max repeat reverse voltage rating, ranging from apx 2v to 5v, and this can be a problem in some apps. Back to back LEDs are immune to this problem. These are available in single colour as well as bicolor types. There are various strategies for reverse voltage handling.

In niche applications such as IR therapy, LEDs are often driven at far above rated current. This causes high failure rate and occasional LED explosions. Thus many parallel strings are used, and a safety screen and ongoing maintenance are required.

Alphanumeric LEDs

These use the same drive strategy as indicator LEDs, the only difference being the larger number of channels, each with its own resistor. 7 segment and starburst LED arrays are available in both common anode or common cathode forms.

Lighting LEDs on mains

A CR dropper followed by full wave rectification is the usual ballast with series-parallel LED clusters.

A single series string minimises dropper losses, while parallelled strings increase reliability. In practice usually 3 strings or more are used.

Operation on square wave and modified sine wave (MSW) sources, such as many invertors, causes heavily increased resistor dissipation in CR droppers, and LED ballasts designed for sine wave use tend to burn on non-sine waveforms. The non-sine waveform also causes high peak LED currents, heavily shortening LED life. An inductor & rectifier makes a more suitable ballast for such use, and other options are also possible.

Lighting LEDs on low voltage

LEDs are normally operated in parallel strings of series LEDs, with the total LED voltage typically adding up to around 2/3 of the supply voltage, and resistor current control for each string.

LED current is proportional to power supply (PSU) voltage minus total LED string voltage. Where battery sources are used, the PSU voltage can vary widely, causing large changes in LED current and light output. For such applications, a constant current regulator is preferred to resistor control. Low drop-out (LDO) constant current regs also allow the total LED string voltage to be a higher percentage of PSU voltage, resulting in improved efficiency and reduced power use.

Torches run 1 or more lighting LEDs on a low voltage battery. These usually use a resistor ballast.

In disposable coin cell powered keyring type LED lights, the resistance of the cell itself is usually the only current limiting device. The cell should not therefore be replaced with a lower resistance type, such as one using a different battery chemistry.

Finally, an LED can be run from a single cell by use of a constant current switched mode invertor. The extra expense makes this option unpopular.

LED panels

The 1,500 foot long LED display on the Fremont Street Experience is currently the largest in the world.

There are two types of LED panels: conventional, using discrete LEDs, and surface mounted device (SMD) panels. Most outdoor screens and some indoor screens are built around discrete LEDs, also known as individually mounted LEDs. A cluster of red, green, and blue diodes is driven together to form a full-color pixel, usually square in shape. These pixels are spaced evenly apart and are measured from center to center for absolute pixel resolution. The largest LED display in the world is over 1,500 foot (457.2 m) long and is located in Las Vegas, Nevada covering the Fremont Street Experience.

Most indoor screens on the market are built using SMD technology—a trend that is now extending to the outdoor market. An SMD pixel consists of red, green, and blue diodes mounted on a chipset, which is then mounted on the driver PC board. The individual diodes are smaller than a pinhead and are set very close together. The difference is that the maximum viewing distance is reduced by 25% from the discrete diode screen with the same resolution.

LED panels allow for smaller sets of interchangeable LEDs to be one large display.

Indoor use generally requires a screen that is based on SMD technology and has a minimum brightness of 600 candelas per square meter (unofficially called nits). This will usually be more than sufficient for corporate and retail applications, but under high ambient-brightness conditions, higher brightness may be required for visibility. Fashion and auto shows are two examples of high-brightness stage lighting that may require higher LED brightness. Conversely, when a screen may appear in a shot on a television show, the requirement will often be for lower brightness levels with lower color temperatures (common displays have a white point of 6500 to 9000 K, which is much bluer than the common lighting on a television production set).

A large LED screen in Razorback Stadium

For outdoor use, at least 2,000 nits are required for most situations, whereas higher brightness types of up to 5,000 nits cope even better with direct sunlight on the screen. (The brightness of LED panels can be reduced from the designed maximum, if required.)

Suitable locations for large display panels are identified by factors such as line of sight, local authority planning requirements (if the installation is to become semi-permanent), vehicular access (trucks carrying the screen, truck-mounted screens, or cranes), cable runs for power and video (accounting for both distance and health and safety requirements), power, suitability of the ground for the location of the screen (if there are no pipes, shallow drains, caves, or tunnels that may not be able to support heavy loads), and overhead obstructions.

Early LED flat panel TV history

The first recorded flat panel LED television screen prototype to be developed was by James P. Mitchell in 1977. The modular, scalable display was enabled by MV50 LEDs and newly available TTL (transistor transistor logic) memory addressing circuit technology. The prototype and paper were displayed at an Engineering Exposition in Anaheim May 1978, and organized by the Science Service in Washington D.C. The LED TV display received special recognition from NASA, General Motors Corporation and area universities including The University of California Irvine, Robert M. Saunders Prof. of Engineering and IEEE President 1977. Additionally, technology business representatives from the U.S. and overseas witnessed operation of the monochromatic LED television display. The prototype remains operational. An LCD (liquid crystal display) matrix design was also presented in the accompanying scientific paper as a future television display method using a similar array scanning design.

The early display prototype was red monochromatic. Low-cost efficient blue LEDs did not emerge until the early 1990s, completing the desired RGB color triad. High-brightness colors gradually emerged in the 1990s enabling new designs for outdoor signage and huge video displays for billboards and stadiums.

Multi-touch sensing

Since LEDs share some basic physical properties with photodiodes, which also use p-n junctions with band gap energies in the visible light wavelengths, they can also be used for photo detection. These properties have been known for some time, but more recently so-called bidirectional LED matrices have been proposed as a method of touch-sensing. In 2003, Dietz, Yerazunis, and Leigh published a paper describing the use of LEDs as cheap sensor devices.

In this usage, various LEDs in the matrix are quickly switched on and off. LEDs that are on shine light onto a user’s fingers or a stylus. LEDs that are off function as photodiodes to detect reflected light from the fingers or stylus. The voltage thus induced in the reverse-biased LEDs can then be read by a microprocessor, which interprets the voltage peaks and then also uses them elsewhere.

Laser

Experiment with a LASER(Light amplified by stimulated emmision of radiation) (US Military)

A laser is an electronic-optical device that produces coherent radiation. The term “laser” is an acronym for Light Amplified by Stimulated Emission of Radiation. A typical laser emits light in a narrow, low-divergence beam and with a well-defined wavelength (i.e., monochromatic, corresponding to a particular colour if the laser is operating in the visible spectrum). This is in contrast to a light source such as the incandescent light bulb, which emits into a large solid angle and over a wide spectrum of wavelength.

A laser consists of a gain medium inside an optical cavity, with a means to supply energy to the gain medium. The gain medium is a material (gas, liquid, solid or free electrons) with appropriate optical properties. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically, one of the two mirrors, the output coupler, is partially transparent. The output laser beam is emitted through this mirror.

Light of a specific wavelength that passes through the gain medium is amplified (increases in power); the surrounding mirrors ensure that most of the light makes many passes through the gain medium. Part of the light that is between the mirrors (i.e., is in the cavity) passes through the partially transparent mirror and appears as a beam of light. The process of supplying the energy required for the amplification is called pumping and the energy is typically supplied as an electrical current or as light at a different wavelength. In the latter case, the light source can be a flash lamp or another laser. Most practical lasers contain additional elements that affect properties such as the wavelength of the emitted light and the shape of the beam.

The first working laser was demonstrated in May 1960 by Theodore Maiman at Hughes Research Laboratories. Recently, lasers have become a multi-billion dollar industry. The most widespread use of lasers is in optical storage devices such as compact disc and DVD players, in which the laser (a few millimeters in size) scans the surface of the disc. Other common applications of lasers are bar code readers and laser pointers. In industry, lasers are used for cutting steel and other metals and for inscribing patterns (such as the letters on computer keyboards). Lasers are also commonly used in various fields in science, especially spectroscopy, typically because of their well-defined wavelength or short pulse duration in the case of pulsed lasers. Lasers are also used for military and medical applications.

A helium-neon laser demonstration at the Kastler-Brossel Laboratory at Univ. Paris 6. The glowing ray in the middle is an electric discharge producing light in much the same way as a neon light. It is the gain medium through which the laser passes, not the laser beam itself, which is visible there. The laser beam crosses the air and marks a red point on the screen to the right.

Spectrum of a helium neon laser showing the very high spectral purity intrinsic to nearly all lasers. Compare with the relatively broad spectral emittance of a light emitting diode.

To edward understand the fundamentals of how lasers work and what makes their emissions so special requires a knowledge of the interaction of electromagnetic radiation and matter (see the “introduction to quantum mechanics” article).

See also: Laser science and Laser construction

A laser is composed of an active laser medium, or gain medium, and a resonant optical cavity. The gain medium transfers external energy into the laser beam. It is a material of controlled purity, size, concentration, and shape, which amplifies the beam by the process of stimulated emission. The gain medium is energized, or pumped, by an external energy source. Examples of pump sources include electricity and light, for example from a flash lamp or from another laser. The pump energy is absorbed by the laser medium, placing some of its particles into high-energy (“excited”) quantum states. Particles can interact with light both by absorbing photons or by emitting photons. Emission can be spontaneous or stimulated. In the latter case, the photon is emitted in the same direction as the light that is passing by. When the number of particles in one excited state exceeds the number of particles in some lower-energy state, population inversion is achieved and the amount of stimulated emission due to light that passes through is larger than the amount of absorption. Hence, the light is amplified. Strictly speaking, these are the essential ingredients of a laser. However, usually the term laser is used for devices where the light that is amplified is produced as spontaneous emission from the same gain medium as where the amplification takes place. Devices where light from an external source is amplified are normally called optical amplifiers.

by stimulated emission is very similar to the input signal in terms of wavelength, phase, and polarization. This gives laser light its characteristic coherence, and allows it to maintain the uniform polarization and often monochromaticity established by the optical cavity design.

The optical cavity, a type of cavity resonator, contains a coherent beam of light between reflective surfaces so that the light passes through the gain medium more than once before it is emitted from the output aperture or lost to diffraction or absorption. As light circulates through the cavity, passing through the gain medium, if the gain (amplification) in the medium is stronger than the resonator losses, the power of the circulating light can rise exponentially. But each stimulated emission event returns a particle from its excited state to the ground state, reducing the capacity of the gain medium for further amplification. When this effect becomes strong, the gain is said to be saturated. The balance of pump power against gain saturation and cavity losses produces an equilibrium value of the laser power inside the cavity; this equilibrium determines the operating point of the laser. If the chosen pump power is too small, the gain is not sufficient to overcome the resonator losses, and the laser will emit only very small light powers. The minimum pump power needed to begin laser action is called the lasing threshold. The gain medium will amplify any photons passing through it, regardless of direction; but only the photons aligned with the cavity manage to pass more than once through the medium and so have significant amplification.

The beam in the cavity and the output beam of the laser, if they occur in free space rather than waveguides (as in an optical fiber laser), are, at best, low order Gaussian beams. However this is rarely the case with powerful lasers. If the beam is not a low-order Gaussian shape, the transverse modes of the beam can be described as a superposition of Hermite-Gaussian or Laguerre-Gaussian beams (for stable-cavity lasers). Unstable laser resonators on the other hand, have been shown to produce fractal shaped beams. The beam may be highly collimated, that is being parallel without diverging. However, a perfectly collimated beam cannot be created, due to diffraction. The beam remains collimated over a distance which varies with the square of the beam diameter, and eventually diverges at an angle which varies inversely with the beam diameter. Thus, a beam generated by a small laboratory laser such as a helium-neon laser spreads to about 1.6 kilometers (1 mile) diameter if shone from the Earth to the Moon. By comparison, the output of a typical semiconductor laser, due to its small diameter, diverges almost as soon as it leaves the aperture, at an angle of anything up to 50°. However, such a divergent beam can be transformed into a collimated beam by means of a lens. In contrast, the light from non-laser light sources cannot be collimated by optics as well or much.

The output of a laser may be a continuous constant-amplitude output (known as CW or continuous wave); or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching. In pulsed operation, much higher peak powers can be achieved.

Some types of lasers, such as dye lasers and vibronic solid-state lasers can produce light over a broad range of wavelengths; this property makes them suitable for generating extremely short pulses of light, on the order of a few femtoseconds (10-15 s).

Although the laser phenomenon was discovered with the help of quantum physics, it is not essentially more quantum mechanical than other light sources. The operation of a free electron laser can be explained without reference to quantum mechanics.

It is understood that the word light in the acronym Light Amplification by Stimulated Emission of Radiation is typically used in the expansive sense, as photons of any energy; it is not limited to photons in the visible spectrum. Hence there are infrared lasers, ultraviolet lasers, X-ray lasers, etc. For example, a source of atoms in a coherent state can be called an atom laser.

Because the microwave equivalent of the laser, the maser, was developed first, devices that emit microwave and radio frequencies are usually called masers. In early literature, particularly from researchers at Bell Telephone Laboratories, the laser was often called the optical maser. This usage has since become uncommon, and as of 1998 even Bell Labs uses the term laser.

History

Foundations

In 1917, Albert Einstein in his paper Zur Quantentheorie der Strahlung (On the Quantum Theory of Radiation), laid the foundation for the invention of the laser and its predecessor, the maser, in a ground-breaking rederivation of Max Planck’s law of radiation based on the concepts of probability coefficients (later to be termed ‘Einstein coefficients’) for the absorption, spontaneous, and stimulated emission.

In 1928, Rudolph W. Landenburg confirmed the existence of stimulated emission and negative absorption.

In 1939, Valentin A. Fabrikant (USSR) predicted the use of stimulated emission to amplify “short” waves.

In 1947, Willis E. Lamb and R. C. Retherford found apparent stimulated emission in hydrogen spectra and made the first demonstration of stimulated emission.

In 1950, Alfred Kastler (Nobel Prize for Physics 1966) proposed the method of optical pumping, which was experimentally confirmed by Brossel, Kastler and Winter two years later.[8]

Maser

In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first microwave amplifier, a device operating on similar principles to the laser, but amplifying microwave rather than infrared or visible radiation. Townes’s maser was incapable of continuous output. Nikolay Basov and Aleksandr Prokhorov of the Soviet Union worked independently on the quantum oscillator and solved the problem of continuous output systems by using more than two energy levels and produced the first maser. These systems could release stimulated emission without falling to the ground state, thus maintaining a population inversion. In 1955 Prokhorov and Basov suggested an optical pumping of multilevel system as a method for obtaining the population inversion, which later became one of the main methods of laser pumping.

Townes reports that he encountered opposition from a number of eminent colleagues who thought the maser was theoretically impossible — including Niels Bohr, John von Neumann, Isidor Rabi, Polykarp Kusch, and Llewellyn H. Thomas.

Townes, Basov, and Prokhorov shared the Nobel Prize in Physics in 1964 “For fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle”.

Laser

In 1957, Charles Hard Townes and Arthur Leonard Schawlow, then at Bell Labs, began a serious study of the infrared laser. As ideas were developed, infrared frequencies were abandoned with focus on visible light instead. The concept was originally known as an “optical maser”. Bell Labs filed a patent application for their proposed optical maser a year later. Schawlow and Townes sent a manuscript of their theoretical calculations to Physical Review, which published their paper that year (Volume 112, Issue 6).

The first page of Gordon Gould’s laser notebook in which he coined the acronym LASER and described the essential elements for constructing one.

At the same time Gordon Gould, a graduate student at Columbia University, was working on a doctoral thesis on the energy levels of excited thallium. Gould and Townes met and had conversations on the general subject of radiation emission. Afterwards Gould made notes about his ideas for a “laser” in November 1957, including suggesting using an open resonator, which became an important ingredient of future lasers.

In 1958, Prokhorov independently proposed using an open resonator, the first published appearance of this idea. Schawlow and Townes also settled on an open resonator design, apparently unaware of both the published work of Prokhorov and the unpublished work of Gould.

The term “laser” was first introduced to the public in Gould’s 1959 conference paper “The LASER, Light Amplification by Stimulated Emission of Radiation”. Gould intended “-aser” to be a suffix, to be used with an appropriate prefix for the spectra of light emitted by the device (x-ray laser = xaser, ultraviolet laser = uvaser, etc.). None of the other terms became popular, although “raser” was used for a short time to describe radio-frequency emitting devices.

Gould’s notes included possible applications for a laser, such as spectrometry, interferometry, radar, and nuclear fusion. He continued working on his idea and filed a patent application in April 1959. The U.S. Patent Office denied his application and awarded a patent to Bell Labs in 1960. This sparked a legal battle that ran 28 years, with scientific prestige and much money at stake. Gould won his first minor patent in 1977, but it was not until 1987 that he could claim his first significant patent victory when a federal judge ordered the government to issue patents to him for the optically pumped laser and the gas discharge laser.

The first working laser was made by Theodore H. Maiman in 1960 at Hughes Research Laboratories in Malibu, California, beating several research teams including those of Townes at Columbia University, Arthur L. Schawlow at Bell Labs, and Gould at a company called TRG (Technical Research Group). Maiman used a solid-state flashlamp-pumped synthetic ruby crystal to produce red laser light at 694 nanometres wavelength. Maiman’s laser, however, was only capable of pulsed operation due to its three energy level pumping scheme.

Later in 1960 the Iranian physicist Ali Javan, working with William R. Bennett and Donald Herriot, made the first gas laser using helium and neon. Javan later received the Albert Einstein Award in 1993.

The concept of the semiconductor laser diode was proposed by Basov and Javan. The first laser diode was demonstrated by Robert N. Hall in 1962. Hall’s device was made of gallium arsenide and emitted at 850 nm in the near-infrared region of the spectrum. The first semiconductor laser with visible emission was demonstrated later the same year by Nick Holonyak, Jr. As with the first gas lasers, these early semiconductor lasers could be used only in pulsed operation, and indeed only when cooled to liquid nitrogen temperatures (77 K).

In 1970, Zhores Alferov in the Soviet Union and Izuo Hayashi and Morton Panish of Bell Telephone Laboratories independently developed laser diodes continuously operating at room temperature, using the heterojunction structure.

Recent innovations

Graph showing the history of maximum laser pulse intensity throughout the past 40 years.

Since the early period of laser history, laser research has produced a variety of improved and specialized laser types, optimized for different performance goals, including:

  • new wavelength bands

  • maximum average output power

  • maximum peak output power

  • minimum output pulse duration

  • maximum power efficiency

  • maximum charging

  • maximum firing

and this research continues to this day.

Lasing without maintaining the medium excited into a population inversion, was discovered in 1992 in sodium gas and again in 1995 in rubidium gas by various international teams. This was accomplished by using an external maser to induce “optical transparency” in the medium by introducing and destructively interfering the ground electron transitions between two paths, so that the likelihood for the ground electrons to absorb any energy has been cancelled.

In 1985 at the University of Rochester’s Laboratory for Laser Energetics a breakthrough in creating ultrashort-pulse, very high-intensity (terawatts) laser pulses became available using a technique called chirped pulse amplification, or CPA, discovered by Gérard Mourou. These high intensity pulses can produce filament propagation in the atmosphere.

Continuous wave and pulsed lasing

A laser may either be built to emit a continuous beam or a train of short pulses. This makes fundamental differences in construction, usable laser media, and applications.

Continuous wave operation

In the continuous wave (CW) mode of operation, the output of a laser is relatively consistent with respect to time. The population inversion required for lasing is continually maintained by a steady pump source.

Pulsed operation

In the pulsed mode of operation, the output of a laser varies with respect to time, typically taking the form of alternating ‘on’ and ‘off’ periods. In many applications one aims to deposit as much energy as possible at a given place in as short time as possible. In laser ablation for example, a small volume of material at the surface of a work piece might evaporate if it gets the energy required to heat it up far enough in very short time. If, however, the same energy is spread over a longer time, the heat may have time to disperse into the bulk of the piece, and less material evaporates. There are a number of methods to achieve this.

Q-switching

In a Q-switched laser, the population inversion (usually produced in the same way as CW operation) is allowed to build up by making the cavity conditions (the ‘Q’) unfavorable for lasing. Then, when the pump energy stored in the laser medium is at the desired level, the ‘Q’ is adjusted (electro- or acousto-optically) to favorable conditions, releasing the pulse. This results in high peak powers as the average power of the laser (were it running in CW mode) is packed into a shorter time frame.

Modelocking

A modelocked laser emits extremely short pulses on the order of tens of picoseconds down to less than 10 femtoseconds. These pulses are typically separated by the time that a pulse takes to complete one round trip in the resonator cavity. Due to the Fourier limit (also known as energy-time uncertainty), a pulse of such short temporal length has a spectrum which contains a wide range of wavelengths. Because of this, the laser medium must have a broad enough gain profile to amplify them all. An example of a suitable material is titanium-doped, artificially grown sapphire (Ti:sapphire).

The modelocked laser is a most versatile tool for researching processes happening at extremely fast time scales (femtosecond physics and femtosecond chemistry, also called ultrafast science), for maximizing the effect of nonlinearity in optical materials (e.g. in second-harmonic generation, parametric down-conversion, optical parametric oscillators and the like), and in ablation applications. Again, because of the short timescales involved, these lasers can achieve extremely high powers.

Pulsed pumping

Another method of achieving pulsed laser operation is to pump the laser material with a source that is itself pulsed, either through electronic charging in the case of flashlamps, or another laser which is already pulsed. Pulsed pumping was historically used with dye lasers where the inverted population lifetime of a dye molecule was so short that a high energy, fast pump was needed. The way to overcome this problem was to charge up large capacitors which are then switched to discharge through flashlamps, producing a broad spectrum pump flash. Pulsed pumping is also required for lasers which disrupt the gain medium so much during the laser process that lasing has to cease for a short period. These lasers, such as the excimer laser and the copper vapour laser, can never be operated in CW mode.

Gas lasers

Gas lasers using many gases have been built and used for many purposes. They are one of the oldest types of laser.

The helium-neon laser (HeNe) emits at a variety of wavelengths and units operating at 633 nm are very common in education because of its low cost.

Carbon dioxide lasers can emit hundreds of kilowatts at 9.6 µm and 10.6 µm, and are often used in industry for cutting and welding. The efficiency of a CO2 laser is over 10%.

Argon-ion lasers emit light in the range 351-528.7 nm. Depending on the optics and the laser tube a different number of lines is usable but the most commonly used lines are 458 nm, 488 nm and 514.5 nm.

A nitrogen transverse electrical discharge in gas at atmospheric pressure (TEA) laser is an inexpensive gas laser producing UV Light at 337.1 nm.

Metal ion lasers are gas lasers that generate deep ultraviolet wavelengths. Helium-silver (HeAg) 224 nm and neon-copper (NeCu) 248 nm are two examples. These lasers have particularly narrow oscillation linewidths of less than 3 GHz (0.5 picometers), making them candidates for use in fluorescence suppressed Raman spectroscopy.

Chemical lasers

Chemical lasers are powered by a chemical reaction, and can achieve high powers in continuous operation. For example, in the Hydrogen fluoride laser (2700-2900 nm) and the Deuterium fluoride laser (3800 nm) the reaction is the combination of hydrogen or deuterium gas with combustion products of ethylene in nitrogen trifluoride. They were invented by George C. Pimentel.

Excimer lasers

Excimer lasers are powered by a chemical reaction involving an excited dimer, or excimer, which is a short-lived dimeric or heterodimeric molecule formed from two species (atoms), at least one of which is in an excited electronic state. They typically produce ultraviolet light, and are used in semiconductor photolithography and in LASIK eye surgery. Commonly used excimer molecules include F2 (fluorine, emitting at 157 nm), and noble gas compounds (ArF [193 nm], KrCl [222 nm], KrF [248 nm], XeCl [308 nm], and XeF [351 nm]).

Solid-state lasers

A 50 W FASOR, based on a Nd:YAG laser, used at the Starfire Optical Range

Solid state laser materials are commonly made by doping a crystalline solid host with ions that provide the required energy states. For example, the first working laser was a ruby laser, made from ruby (chromium-doped corundum). Formally, the class of solid-state lasers includes also fiber laser, as the active medium (fiber) is in the solid state. Practically, in the scientific literature, solid-state laser usually means a laser with bulk active medium; while wave-guide lasers are caller fiber lasers.

Neodymium is a common dopant in various solid state laser crystals, including yttrium orthovanadate (Nd:YVO4), yttrium lithium fluoride (Nd:YLF) and yttrium aluminium garnet (Nd:YAG). All these lasers can produce high powers in the infrared spectrum at 1064 nm. They are used for cutting, welding and marking of metals and other materials, and also in spectroscopy and for pumping dye lasers. These lasers are also commonly frequency doubled, tripled or quadrupled to produce 532 nm (green, visible), 355 nm (UV) and 266 nm (UV) light when those wavelengths are needed.

Ytterbium, holmium, thulium, and erbium are other common dopants in solid state lasers. Ytterbium is used in crystals such as Yb:YAG, Yb:KGW, Yb:KYW, Yb:SYS, Yb:BOYS, Yb:CaF2, typically operating around 1020-1050 nm. They are potentially very efficient and high powered due to a small quantum defect. Extremely high powers in ultrashort pulses can be achieved with Yb:YAG. Holmium-doped YAG crystals emit at 2097 nm and form an efficient laser operating at infrared wavelengths strongly absorbed by water-bearing tissues. The Ho-YAG is usually operated in a pulsed mode, and passed through optical fiber surgical devices to resurface joints, remove rot from teeth, vaporize cancers, and pulverize kidney and gall stones.

Titanium-doped sapphire (Ti:sapphire) produces a highly tunable infrared laser, commonly used for spectroscopy as well as the most common ultrashort pulse laser.

Thermal limitations in solid-state lasers arise from unconverted pump power that manifests itself as heat and phonon energy. This heat, when coupled with a high thermo-optic coefficient (dn/dT) can give rise to thermal lensing as well as reduced quantum efficiency. These types of issues can be overcome by another novel diode-pumped solid state laser, the diode-pumped thin disk laser. The thermal limitations in this laser type are mitigated by utilizing a laser medium geometry in which the thickness is much smaller than the diameter of the pump beam. This allows for a more even thermal gradient in the material. Thin disk lasers have been shown to produce up to kilowatt levels of power.

Fiber-hosted lasers

Solid-state lasers where the light is guided due to the total internal reflection in a wavequide are called fiber lasers because of huge ratio of the length to the transversal size; this ratio may vary from 106 to 109; visually, the active element of such a laser looks as a fiber. Guiding of light allows extremely long gain regions providing good cooling conditions; fibers have high surface area to volume ratio allows efficient cooling. In addition, the fiber’s waveguiding properties tend to reduce thermal distortion of the beam.

double-clad fibers. Quite often, the fiber laser is designed as a double-clad fiber. This type of fiber consists of a fiber core, an inner cladding and an outer cladding. The index of the three concentric layers is chosen so that the fiber core acts as a single-mode fiber for the laser emission while the outer cladding acts as a highly multimode core for the pump laser. This lets the pump propagate a large amount of power into and through the active inner core region, while still having a high numerical aperture (NA) to have easy launching conditions.

Fiber disk lasers. The efficient use of pump in fiber laser can be achieved at the transversal delivery of pump; however, several lasers should be formed into a stack. Such stack may have shape of a disk, which is an alternative to the double-clad fiber.

Maximal length of a fiber laser. Fiber lasers have a fundamental limit in that the intensity of the light in the fiber cannot be so high that optical nonlinearities induced by the local electric field strength can become dominant and prevent laser operation and/or lead to the material destruction of the fiber. This effect is called photodarkening. In bulk laser materials, the cooling is not so efficient, and it is difficult to separate the effects of photodarkening from the thermal effects, but the experiments in fibers the photodarkening can be attributed to the forming og long-living color centers.

Semiconductor lasers

Commercial laser diodes emit at wavelengths from 375 nm to 1800 nm, and wavelengths of over 3 µm have been demonstrated. Low power laser diodes are used in laser printers and CD/DVD players. More powerful laser diodes are frequently used to optically pump other lasers with high efficiency. The highest power industrial laser diodes, with power up to 10 kW, are used in industry for cutting and welding. External-cavity semiconductor lasers have a semiconductor active medium in a larger cavity. These devices can generate high power outputs with good beam quality, wavelength-tunable narrow-linewidth radiation, or ultrashort laser pulses.

Vertical cavity surface-emitting lasers (VCSELs) are semiconductor lasers whose emission direction is perpendicular to the surface of the wafer. VCSEL devices typically have a more circular output beam than conventional laser diodes, and potentially could be much cheaper to manufacture. As of 2005, only 850 nm VCSELs are widely available, with 1300 nm VCSELs beginning to be commercialized, and 1550 nm devices an area of research. VECSELs are external-cavity VCSELs. Quantum cascade lasers are semiconductor lasers that have an active transition between energy sub-bands of an electron in a structure containing several quantum wells.

The development of a silicon laser is important in the field of optical computing, since it means that if silicon, the chief ingredient of computer chips, were able to produce lasers, it would allow the light to be manipulated like electrons are in normal integrated circuits. Thus, photons would replace electrons in the circuits, which dramatically increases the speed of the computer. Unfortunately, silicon is a difficult lasing material to deal with, since it has certain properties which block lasing. However, recently teams have produced silicon lasers through methods such as fabricating the lasing material from silicon and other semiconductor materials, such as indium(III) phosphide or gallium(III) arsenide, materials which allow coherent light to be produced from silicon. These are called hybrid silicon laser. Another type is a Raman laser, which takes advantage of Raman scattering to produce a laser from materials such as silicon.

Dye lasers

Dye lasers use an organic dye as the gain medium. The wide gain spectrum of available dyes allows these lasers to be highly tunable, or to produce very short-duration pulses (on the order of a few femtoseconds)

Free electron lasers

Free electron lasers, or FELs, generate coherent, high power radiation, that is widely tunable, currently ranging in wavelength from microwaves, through terahertz radiation and infrared, to the visible spectrum, to soft X-rays. They have the widest frequency range of any laser type. While FEL beams share the same optical traits as other lasers, such as coherent radiation, FEL operation is quite different. Unlike gas, liquid, or solid-state lasers, which rely on bound atomic or molecular states, FELs use a relativistic electron beam as the lasing medium, hence the term free electron.

Nuclear reaction lasers

In September 2007, the BBC News reported that there was speculation about the possibility of using positronium annihilation to drive a very powerful gamma ray laser. This laser is believed to be powerful enough to jump-start a nuclear reaction, with a single gamma ray laser, rather than the hundreds of conventional lasers involved in current experiments.

Uses

Lasers range in size from microscopic diode lasers (top) with numerous applications, to football field sized neodymium glass lasers (bottom) used for inertial confinement fusion, nuclear weapons research and other high energy density physics experiments.

When lasers were invented in 1960, they were called “a solution looking for a problem”.[citation needed] Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, and the military.

The first application of lasers visible in the daily lives of the general population was the supermarket barcode scanner, introduced in 1974. The laserdisc player, introduced in 1978, was the first successful consumer product to include a laser, but the compact disc player was the first laser-equipped device to become truly common in consumers’ homes, beginning in 1982, followed shortly by laser printers.

Some of the other applications include:

  • Medicine: Bleedless surgery, laser healing, survical treatment, kidney stone treatment, eye treatment, dentistry

  • Industry: Cutting, welding, material heat treatment, marking parts

  • Defense: Marking targets, guiding munitions, missile defence, electro-optical countermeasures (EOCM), RADAR alternative

  • Research: Spectroscopy, laser ablation, Laser annealing, laser scattering, laser interferometry, LIDAR

  • Product development/Commercial: Laser Printers, CDs, Barcode scanners, laser pointers, Holograms)

In 2004, excluding diode lasers, approximately 131,000 lasers were sold world-wide, with a value of US$2.19 billion. In the same year, approximately 733 million diode lasers, valued at $3.20 billion, were sold.

Example uses by typical output power

Different uses need lasers with different output powers. Many lasers are designed for a higher peak output with an extremely short pulse, and this requires different technology from a continuous wave (constant output) lasers, as are used in communication, or cutting. Output power is always less than the input power needed to generate the beam.

The peak power required for some uses:

  • 5 mW – CD-ROM drive

  • 5-10 mW – DVD player

  • 100 mW – CD-R drive

  • 250 mW – output power of Sony SLD253VL red laser diode, used in consumer 48-52 speed CD-R burner.

  • 500 mW – output power of Sony SLD1332V red laser diode, used in consumer DVD-R burner.

  • 1 W – green laser in current Holographic Versatile Disc prototype development.

  • 100 to 3000 W (peak output 1.5 kW) – typical sealed CO2 lasers used in industrial laser cutting.

  • 1 kW – Output power expected to be achieved by “a single 1 cm diode laser bar”

  • 700 terawatts (TW) – The National Ignition Facility is working on a system that, when complete, will contain a 192-beam, 1.8-megajoule laser system adjoining a 10-meter-diameter target chamber. The system is expected to be completed in April of 2009.

  • 1.25 petawatts (PW) – world’s most powerful laser (claimed on 23 May 1996 by Lawrence Livermore Laboratory).

From : My teacher Aplication notes, LED.

Click this for such Information above, producer of LED : http://www.maxim-ic.com/ LED are still popular.

http://pdfserv.maxim-ic.com/en/an/AN1883.pdf complete data sheet in PDF versions.

Hopely useful. Regards : Yonni. M

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Multisystems of all Colour Video

Posted by yonni1967 on September 5, 2008

Multisystems of all Colour Video

Information below for student who’s concerning in video colour of the world.

Source information we find from : www.wikipedia.com

What are NTSC, PAL and SECAM?

NTSC (National Television Standards Committee) is a standard used in North America and Japan. It has the ability to display up to 525 lines of resolution. PAL (Phase Alternating Line), a standard used almost everywhere else in the world, has the ability to display 625 lines of resolution. SECAM (Sequential Color Memory) is used sparingly around the world and can be found in France, parts of Greece, Eastern Europe, Russia, Africa and a few other parts of the world. However, any SECAM country can display PAL tapes in full color, but not all PAL countries can display all SECAM tapes in color. Only if they are true SECAM and not MESECAM can those VCR’s display SECAM.

What video standard does my country use?

If you’re in North America, Japan, Korea, the Philippines and parts of South America, you use NTSC. Most other areas of the world use PAL or SECAM. Half of Brazil uses NTSC while the other half uses PAL-M. Argentina, Uruguay and Paraguay use PAL-N. The rest of the world uses mainly PAL. If you’re unsure what your video standard is, contact your local cable or broadcast company. Also, on the back of most videotape is indicating what video standard the tape is. This is a good representation of what your video standard is.

Do I need special types of videotapes to record in different video standards?

No, videotapes are blank. You can get a blank tape and record any video standard onto it.

How do I watch overseas videotapes?

Videotapes come in variety standards, each incompatible with the other. To watch videotapes from overseas that are not the same video standard as your own, you’ll need what is called a multisystem VCR and a multisystem TV, or a Digital Video Standards Converter and VCR, or a VCR with a built-in Converter.

What is a multisystem VCR?

Different areas of the world use different video standards. North America uses NTSC, Europe uses PAL and SECAM, and South America uses PAL-M, PAL-N, PAL and NTSC. Almost every area of the world has a mixture of video standards. Unfortunately, none of these standards are compatible with each other. A multisystem VCR has the ability to play videotapes of different video standards.

Country

Voltage

Frequency

TV System

Afghanistan

220V

50Hz

B/PAL B/SECAM

Albania

220V

50Hz

B.G/PAL

Algeria

127/220V

50Hz

B/PAL

Argentina

220V

50Hz

N/PAL

Australia

240V

50Hz

B.G/PAL

Austria

220V

50Hz

B.G/PAL

Bangladesh

230V

50Hz

B/PAL

Belgium

220V

50Hz

B.H/PAL

Bolivia

110/220V

50/60Hz

N/PAL

Brazil

110/127/220V

60Hz

M/PAL

Brunei

240V

50Hz

B/PAL

Bulgaria

220V

50Hz

D.K/SECAM

Canada

120/230V

60Hz

M/NTSC

Canary Islands

110/220V

50Hz

B.G/PAL

Chile

220V

50Hz

M/NTSC

China

220V

50Hz

D/PAL

Columbia

110/120V

60Hz

M/NTSC

Congo (P. R.)

220V

50Hz

D/SECAM

Costa Rica

120V

60Hz

M/NTSC

Cyprus

240V

50Hz

B.G/PAL

Czechoslovakia

220V

50Hz

D.K/SECAM

Denmark

220V

50Hz

B.G/PAL

Dominican Republic

110V

60Hz

M/NTSC

Ecuador

110V

60Hz

M/NTSC

Egypt

110/220V

50Hz

B/SECAM

El Salvador

110V

60Hz

M/NTSC

Fiji

240V

50Hz

M/NTSC

Finland

220V

50Hz

B.G/PAL

France

127/220V

50Hz

E.L/SECAM

Germany

220V

50Hz

B.G/SECAM/PAL

Gibraltar

240V

50Hz

B.G/PAL

Greece

220V

50Hz

B.G/SECAM

Guam

110V

60Hz

M/NTSC

Guatemala

110/120V

60Hz

M/NTSC

Honduras

110V

60Hz

M/NTSC

Hong Kong

200V

50Hz

I/PAL

Hungary

220V

50Hz

D.K/SECAM

India

230V

50Hz

B/PAL

Indonesia

127/220V

50Hz

B.G/PAL

Iran

220V

50Hz

B/SECAM

Iraq

220V

50Hz

B/SECAM

Ireland

220V

50Hz

AI/PAL

Israel

230V

50Hz

B.G/PAL

Italy

125/220V

50Hz

B.G/PAL

Jamaica

110/220V

50Hz

M/NTSC

Jordan

220V

50Hz

B.G/PAL

Kenya

240V

50Hz

B/PAL

Korea (D. P. R.)

220V

50Hz

D/SECAM

Korea (Rep.)

100/200V

60Hz

M/NTSC

Kuwait

240V

50Hz

B/PAL

Lebanon

110/190V

50Hz

B/SECAM

Liberia

120V

60Hz

B/PAL

Libya

127/230V

50Hz

B/SECAM

Luxembourg

120/220V

50Hz

C/PAL, GL/SECAM

Macao

110/220V

50Hz

I/PAL

Malaysia

240V

50Hz

B/PAL

Mexico

110/220V

50Hz

M/NTSC

Monaco

220V

50Hz

C/PAL, GL/SECAM

Mongolia

220V

50Hz

D/SECAM

Morocco

115/220V

50Hz

B/SECAM

Myanmar

230V

50Hz

M/NTSC

Netherlands

220V

50Hz

B.G/PAL

New Caledonia

220V

50Hz

K1/SECAM

New Zealand

230V

50Hz

B/PAL

Nicaragua

120V

60Hz

M/NTSC

Niger

220V

50Hz

K1/SECAM

Nigeria

230V

50Hz

BG/PAL

Norway

230V

50Hz

B.G/PAL

Oman

220V

50Hz

B.G/PAL

Pakistan

230V

50Hz

B/PAL

Panama

110/120V

60Hz

M/NTSC

Paraguay

220V

50Hz

N/PAL

Peru

220V

60Hz

M/NTSC

Philippines

110/220V

60Hz

M/NTSC

Poland

220V

50Hz

D.K/SECAM

Portugal

220V

50Hz

B.G/PAL

Puerto Rico

120V

60Hz

M/NTSC

Qatar

240V

50Hz

B/PAL

Rumania

220V

50Hz

D.K/PAL

Saudi Arabia

127/220V

50/60Hz

B.G/SECAM, PAL

Singapore

230V

50Hz

B/PAL

South Africa

220/230V

50Hz

I/PAL

Spain

127/220V

50Hz

B.G/PAL

Sri Lanka

230V

50Hz

B/PAL

Sweden

220V

50Hz

B.G/PAL

Switzerland

220V

50Hz

B.G/PAL

Syria

115/200V

50Hz

B/SECAM

Taiwan

110V

60Hz

M/NTSC

Thailand

220V

50Hz

B/PAL

Turkey

220V

50Hz

B/PAL

United Arab Emirates

220V

50Hz

B/PAL

United Kingdom

240V

50Hz

I/PAL

Uruguay

220V

50Hz

N/PAL

USA

120V

60Hz

M/NTSC

C. I. S.

127/220V

50Hz

D.K/SECAM

Venezuela

120V

50/60Hz

N/NTSC

Vietnam

120/220V

50Hz

M/NTSC, D/SECAM

Yemen

230V

50Hz

B/PAL

Yugoslavia

220V

50Hz

B.G/PAL

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