Nheyo yekushanda yePhotodiodes nePhototransistors
Kuvandudzwa kwetekinoroji yemazuva ano yemagetsi kunonyanya kutsamira pamidziyo yekuona chiedza inokwanisa "kuona" chiedza uye kuchishandura kuita masaini emagetsi. Zvinhu zviviri zvinonyanya kushandiswa pachinangwa ichi iphotodiodes nephototransistors. Ose ari maviri ndeemhuri yemasemiconductor anonzwa chiedza, anoshandiswa zvakanyanya mumasystem e automation, optical communications, measurements, uye consumer devices dzakadai se remote controls, printers, uye light sensors mumafoni. Kunyangwe ese ari maviri achipindura chiedza, maphotodiodes nephototransistors ane misimboti yekushanda yakasiyana, hunhu, uye mashandisirwo. Chinyorwa chino chinokurukura misimboti yekushanda kwavo zvakadzama, vachienzanisa, uye vachipa mienzaniso yemashandisirwo avo.
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1. Nheyo dzeKuona Chiedza muSemiconductors
Kuti tinzwisise maphotodiode nemaphototransistors, tinofanira kurangarira pfungwa huru yemasemiconductors: machaji anotakura, maerekitironi nemaburi. Kana chiedza (maphotoni) chichirova chinhu chesemiconductor, chinopa simba maerekitironi, zvichiita kuti afambe kubva pabhandi revalence kuenda kubhandi rekufambisa. Maitiro aya anogadzira maerekitironi nemaburi maviri. Maphotoni akawanda paanonyudzwa, ndipo paanoumbwa machaji akawanda, zvichiwedzera huwandu hwemagetsi anogona kuyerera.
Pfungwa huru ndeyekuti: chiedza chinokonzera shanduko muhunhu hwemagetsi hwezvikamu. Shanduko idzi dzinogona kuva muchimiro chekuwedzera kwemagetsi, kudzikira kweresistance, kana kuoneka kwevoltage. Mumaphotodiode nemaphototransistors, shanduko huru inoonekwa mumagetsi.
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2. Nheyo yekushanda yePhotodiode
a. Maumbirwo uye Maitiro Ekushanda
Photodiode chaizvoizvo iPN diode (kana kuti misiyano yakaita sePIN uye avalanche photodiodes) yakagadzirirwa kuti inzwe chiedza. Chimiro chePN chinoumba nzvimbo yekushaikwa kwechiedza, nzvimbo isina ma free charge carriers anoshanda se "charged separation zone".
Mafotodiode anogona kushanda nenzira dzakasiyana-siyana, asi anonyanya kushandiswa ndeaya:
1. Modhi yekufambisa mifananidzo (reverse bias)
Photodiode ine rusaruro rwekumashure. Nzvimbo yekuderera kwesimba inokura, mhinduro inokura nekukurumidza, capacitance inoderera, uye linearity inowanzo kuve yakanaka. Iyi modhi yakajairika kumasensa nekutaurirana kwemaziso.
2. Modhi ye photovoltaic (hapana rusaruro/zero rusaruro)
Maphotodiode haana kutsamira padivi rekunze. Chiedza chinouya chinoburitsa voltage yakafanana nesero rezuva, kunyangwe riri diki. Izvi zvine mukana wekuti ruzha rudzikire, zvichiita kuti zvikwanise kuyerwa, asi mhinduro yacho inogona kunonoka pane reverse bias.
b. Maitiro ekushandura chiedza kuita magetsi
Kana photodiode yaiswa pachiedza:
1. Maphotoni anonyudzwa munzvimbo inoperera kana pedyo nenzvimbo inoungana.
2. Peya yemaerekitironi nemaburi inoumbwa.
3. Munda wemagetsi wemukati uri pamharadzano unoparadzanisa vaviri ava:
- Maerekitironi anosundirwa kudivi reN
- Buri rakasundirwa kudivi reP
4. Kupatsanurwa kwechaji uku kunoita kuti pave ne photocurrent.
Kubuda kwese kunowanzova musanganiswa we:
– Mhepo ine rima: mhepo diki inoyerera kunyangwe isina chiedza (nekuda kwemhedzisiro yekupisa).
– Photocurrent: simba remagetsi rinoenderana nesimba rechiedza.
Muchidimbu, chiedza chinowedzera kupenya → photocurrent inowedzerawo.
c. Hunhu hwePhotodiodes
Zvimwe zvinhu zvakakosha zve photodiodes zvinosanganisira:
- Mhinduro inokurumidza (yakakodzera masaini efrequency yakakwira)
- Kusimba kwechiedza kubva pamutsetse kuenda kuchiedza pane imwe nzvimbo
– Kubuda kwemagetsi kudiki kana tichienzanisa ne phototransistor, saka kazhinji inoda amplifier (op-amp/transimpedance amplifier)
– Ruzha nerima remhepo zvinhu zvakakosha pakushandisa zvinhu nemazvo.
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3. Nheyo yekushanda kwePhototransistor
a. Maumbirwo Ekutanga ePhototransistor
Mu phototransistor, chiedza chinoshanda se "base current" inodzora collector-emitter current.
Kusiyana nemaphotodiode, ayo anogadzira magetsi zvakananga kubva kuphoton effect, maphototransistors anoshandisa gain yetransistor. Nekuda kwegain, gain ye phototransistor inogona kukura zvakanyanya.
b. Maitiro Ekushanda: Chiedza Sechinotsiva Simba Remagetsi
Mashandiro ayo anogona kutsanangurwa seinotevera:
1. Chiedza chinobaya nzvimbo yechigadziko-chinounganidza (kazhinji panosangana BC).
2. Mapairi emaerekitironi nemaburi anoumbwa nekuda kwekutorwa kwephoton.
3. Izvi zvinogadzira simba diki rakaenzana nesimba remagetsi remufananidzo.
4. Mu transistor yeBJT, simba remuunganidzi rinenge:
\[
I_C \approx \beta \cdot I_B
\]
Sezvo \(I_B \) "yakagadzirwa" nechiedza, chiedza chinotonga \(I_C \).
Nekuda kweizvozvo, shanduko diki mukusimba kwechiedza dzinogona kukonzera shanduko huru mu collector current kupfuura mu photodiode, nekuda kwe gain factor \(\beta\).
c. Maitiro eSekitori uye Kuitwa
Maphototransistors anowanzo shandiswa nenzira dzinotevera:
– Common emitter: collector kuenda kuvoltage kuburikidza ne resistor, output pacollector. Kana yaiswa pachiedza, transistor inenge "YAKAVHARWA" zvakanyanya, output voltage inochinja.
– Muunganidzi wezvinhu zvakajairika (muteveri wemitter): chinobuda pamitter, chinobatsira kune vamwe asi chisingawanzoitiki mumasensa ari nyore.
Dzimwe nguva ma phototransistors anobvisa base pin (3-pin), asi mazhinji ane 2-pin chete (internal base haisvikiki).
d. Hunhu hwePhototransistors
- Inonyanya kunzwisisika (inoburitsa simba rakawanda)
- Inononoka kupfuura mafotodiode nekuda kwemaitiro ekuchengetedza chaji uye simba re transistor
- Inowanzova isina kurongeka zvakanyanya pasi pemamwe mamiriro ezvinhu, kunyanya pedyo nekuzara
- Yakakodzera kuona chiedza/rima, kuona zvinhu, ma optocouplers, ma revolution counters, uye mashandisirwo ari nyore ekudzora.
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4. Kuenzanisa kwePhotodiode vs Phototransistor
Heino pfupiso yemisiyano mikuru:
1. Kumhanya kwekupindura
– Photodiode: inokurumidza zvikuru (yakanakira kutaurirana kwemaziso, inochinja-chinja nekukurumidza)
– Phototransistor: inononoka (yakakwana kune masensa akajairika)
2. Kunzwa / kuwedzera simba
– Photodiode: simba diki, rinowanzoda kuwedzerwa
– Phototransistor: simba guru remagetsi nekuda kwekuwedzera kwe transistor
3. Kurongeka
- Photodiodes: kazhinji yakatwasuka
- Phototransistor: inogona kunge isina mutsara, isina kuzara
4. Nhevedzano
– Photodiode: inowanzoda dunhu re amplifier rinoshandisa magetsi kusvika pamagetsi
- Phototransistor: inogona kushandiswa zvakananga ne resistor iri nyore yekutakura
5. Kushandiswa
– Photodiodes: fiber optic communication, ma sensors ekunyatsojeka, kuyerwa kwechiedza kwakagadziriswa
- Phototransistors: zvinhu zvinoona zvinhu, ma sensor emutsara, ma optocouplers, ma switch emwenje
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5. Mienzaniso yeMashandisirwo Muhupenyu Hwechokwadi
1. Chivharo cheOptocoupler
Mazhinji ma optocouplers anoshandisa phototransistors nekuti chiratidzo chekubuda chinofanira kunge chakakura zvakakwana kuti chifambise ma digital kana switching circuits.
2. Mugamuchiri we infrared
MumaIR receivers (remotes), maphotodiodes kana maIR receiver modules ane ma amplifiers emukati anowanzo shandiswa nekuti anoda mhinduro inokurumidza ku modulation (semuenzaniso 38 kHz).
3. Chinongedzo chemutsetse parobhoti
Maphototransistors anowanzo shandiswa nemaIR LED sematransmitter ekuverenga chiedza chinobva panzvimbo nhema/chena.
4. Chiyero chechiedza
Mafotodiodhi anonyanya kukodzera michina inoda kurongeka kwakasimba uye kurongeka.
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6. Kesimpulan
Maphotodiode nemaphototransistors ese anoshandura chiedza kuita masaini emagetsi, asi anoshanda achishandisa nzira dzakasiyana. Maphotodiode anoshandisa kuumbwa kwema electron-hole paPN junction kugadzira photocurrent inokurumidza uye ine linear, zvichiita kuti ive yakakodzera kushandiswa nekukurumidza uye kuyera kwakarurama. Kune rumwe rutivi, maPhototransistors anoshandisa mhedzisiro yechiedza "kutsiva" base current uye wobva waiwedzera kuburikidza nekuwedzera kwe transistor, zvichiita kuti ive nyore kushandisa uye ive nyore kushandisa muma circuits akareruka, kunyangwe kazhinji kacho isinganyanyi kunonoka uye isina linear.
Nekunzwisisa mashandiro anoita zvese izvi, tinogona kusarudza zvikamu zvakakodzera zvatinoda: kungave tiri kutsvaga kumhanya uye kururama (photodiodes) kana kuti kunzwa uye nyore (phototransistors). Kana zvikashandiswa nemazvo, zvese zviri zviviri zvakakosha kumasisitimu emazuva ano e optical sensor.
