Te Mātāpono Mahi o ngā Photodiode me ngā Phototransistors
Ko te whanaketanga o te hangarau hiko hou e whakawhirinaki nui ana ki ngā taputapu pūoko e kaha ana ki te "kite" i te mārama me te huri i aua mea hei tohu hiko. Ko ngā wāhanga e rua e whakamahia whānuitia ana mō tēnei kaupapa ko ngā photodiode me ngā phototransistors. Nō te whānau o ngā semiconductors e aro ana ki te mārama, e whakamahia whānuitia ana i roto i ngā pūnaha aunoa, ngā whakawhitiwhiti kōrero whatu, ngā taputapu ine , me ngā taputapu kaihoko pēnei i ngā mana mamao, ngā pūreretā, me ngā pūoko mārama i roto i ngā waea pūkoro. Ahakoa e aro ana ngā mea e rua ki te mārama, he rerekē ngā mātāpono mahi, ngā āhuatanga, me ngā tono a ngā photodiode me ngā phototransistors. Ka matapakihia e tēnei tuhinga ō rāua mātāpono mahi, ka whakatauritehia, ka whakaratohia hoki he tauira o ā rāua tono.
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1. Ngā Kaupapa Taketake o te Pūrongo Mārama i roto i ngā Ārahi-ā-Irahiko
Hei mārama ki ngā photodiode me ngā phototransistors, me maumahara tātou ki te ariā matua o ngā semiconductors: ngā kaikawe utu, ngā irahiko me ngā kōhao. Ina pā te mārama (ngā photons) ki tētahi rauemi semiconductor, ka whakakahangia ngā irahiko, ka neke atu i te roopu valence ki te roopu conduction. Ka hangaia e tēnei tukanga he takirua irahiko-kōhao. Ko te nui ake o ngā photons e mimitihia ana, ko te nui ake o ngā takirua kaikawe utu ka hangaia, ka piki ake te nui o te iahiko ka taea te rere.
Ko te kaupapa matua: ka puta ngā panoni i ngā āhuatanga hiko o ngā wāhanga mā te mārama. Ka taea ēnei panoni te puta mai i te pikinga o te iahiko, te hekenga o te ātete, te putanga mai rānei o te ngaohiko. I roto i ngā photodiode me ngā phototransistors, ko te panonitanga matua ka kitea i roto i te iahiko.
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2. Te Mātāpono Mahi o te Photodiode
a. Hanganga me te Aratau Whakahaere
Ko te photodiode he PN diode (he momo rerekētanga pēnei i te PIN me te avalanche photodiode) i hangaia kia aro ki te mārama. Ka hangaia e te hanganga PN he rohe mimiti, he rohe kāore he kaikawe utu kore e mahi ana hei "rohe wehenga" kua utua.
He maha ngā momo mahi a ngā photodiode, engari ko ngā momo e whakamahia whānuitia ana ko:
1. Aratau kawe whakaahua (whakamuri whakamuri)
He whakahurihuri te whakapūnga o te photodiode. Ka whānui ake te rohe whakahekenga, ka tere ake te urupare, ka heke te kaha, ā, he pai te rārangi. He mea noa tēnei aratau mō ngā pūoko me ngā whakawhitiwhitinga whatu.
2. Aratau photovoltaic (kāore he pānga/kore pānga)
Kāore ngā photodiode e pāngia e te pānga ki waho. Ka puta he ngaohiko e rite ana ki te pūtau rā, ahakoa he iti ake. Ko te painga o tēnei ko te iti o te haruru, e pai ai mō ētahi inenga, engari ka puhoi ake te urupare i te pānga whakamuri.
b. Te Tikanga o te Huri i te Mārama hei Iahiko
Ina pāngia te photodiode e te māramatanga:
1. Ka mimitia ngā photon i te rohe mimiti, i te taha rānei o te hononga.
2. Ka hangaia he takirua irahiko-pōro.
3. Mara hiko ka wehea te takirua e te hononga o roto:
– Ka panaia ngā irahiko ki te taha N
– Kua panaia te kōhao ki te taha P
4. Ka puta he iahiko whakaahua i tēnei wehenga utu.
Ko te rerenga katoa he huinga o:
– Te au pōuri: he au iti e rere ana ahakoa kāore he māramatanga (nā ngā pānga o te wera).
– Te au whakaahua: te au e ōrite ana ki te kaha o te mārama.
I te kīanga māmā noa, ka mārama ake te mārama → ka nui ake te iahiko whakaahua.
c. Ngā Āhuatanga o ngā Photodiode
Ko ētahi o ngā āhuatanga nui o ngā photodiode ko:
– Tauhohenga tere (e tika ana mō ngā tohu auau teitei)
– Te kaha o te māramatanga mai i te rārangi ki te kaha o te māramatanga i roto i tētahi whānuitanga kua whakaritea
– He iti noa te ia putanga ki te whakatauritea ki te phototransistor, nō reira he maha ngā wā ka hiahiatia he whakakaha (op-amp/transimpedance whakakaha)
– He mea nui te haruru me te ia pōuri i roto i ngā tono tika.
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3. Te Mātāpono Mahi o te Phototransistor
a. Hanganga Taketake o te Phototransistor
Ko te phototransistor he transistor BJT (ko te tikanga he NPN) ko tōna turanga he mea aro ki te mārama. I roto i te phototransistor, ka mahi te mārama hei "au turanga" e whakahaere ana i te au kaikohi-kaituku.
Kāore i rite ki ngā photodiode, e whakaputa tika ana i te iahiko mai i te pānga photon, ka whakamahia e ngā phototransistors te whakanui o te transistor. Nā te whakanui, ka nui ake te iahiko putanga o te phototransistor.
b. Tikanga Mahi: Mārama hei Whakakapinga mō te Au Pūtake
Ka taea te whakamārama i tana mahi penei:
1. Ka pā te mārama ki te rohe turanga–kohikohi (ko te hononga BC te tikanga).
2. Ka hangaia ngā takirua irahiko-pū nā te mimiti o te photon.
3. Ka puta he iahiko iti e rite ana ki te iahiko pūtake whakaahua i tēnei pānga.
4. I roto i te transistor BJT, ko te iahiko kohikohi he tata ki:
\[
I_C \tata \beta \cdot I_B
\]
Nā te mārama i "hanga" ai a \( I_B \), mā te mārama e whakahaere a \( I_C \).
Nā reira, mā ngā panonitanga iti o te kaha o te mārama ka nui ake ngā panonitanga o te iahiko kohikohi i tērā o te photodiode, nā te tauwehenga whakanui \(\beta\).
c. Aratau Porowhita me te Whakatinanatanga
E whakamahia ana ngā phototransistors i ngā momo e whai ake nei:
– Kaituku noa: te kaikohi ki te ngaohiko mā roto i tētahi ātete, ka puta te putanga ki te kaikohi. Ina pāngia e te mārama, ka "ON" ake te transistor, ka rerekē te ngaohiko putanga.
– Kaikohi noa (kaitātari tuku): putanga i te kaituku, he mea whai hua mō ētahi wā engari he iti ake te kitea i roto i ngā pūoko māmā.
I ētahi wā ka tangohia te titi turanga (3-pine) o ngā phototransistors, engari he maha anō hoki he 2-pine anake (kāore e taea te uru atu ki te turanga o roto).
d. Ngā Āhuatanga o ngā Phototransistors
– He tairongo ake (he nui ake te iahiko putanga)
– He puhoi ake i ngā photodiode nā te tukanga rokiroki utu me ngā āhuatanga o te transistor
– Kāore i te tino rārangi i raro i ētahi āhuatanga, inā koa tata ki te mākū
– He pai mō te kimi māramatanga/pōuri, te pūoko ahanoa, ngā hononga opto, ngā kaute hurihanga, me ngā tono whakahaere māmā.
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4. Te whakataurite i te Photodiode me te Phototransistor
Anei te whakarāpopototanga o ngā rerekētanga matua:
1. Te tere o te urupare
– Whakaahua-ira: tino tere (he pai mō ngā whakawhitiwhitinga whatu, he tere te whakarerekētanga)
– Phototransistor: puhoi ake (he rawaka mō ngā pūoko whānui)
2. Te aro / te whakanui
– Teiōra Whakaahua: he iti te iahiko, he maha ngā wā ka hiahiatia he whakanui
– Phototransistor: he nui ake te iahiko nā te whakanui transistor
3. Te Raina
– Ngā taiohiko whakaahua: he rārangi ake te nuinga
– Phototransistor: ka taea te kore-raina, ka ngāwari te whakakī
4. Raupapa
– Photodiode: he maha ngā wā ka hiahiatia he ara iahiko whakakaha au-ki-ngaohiko
– Phototransistor: ka taea te whakamahi tika me te ātete kawenga māmā
5. Tono
– Ngā taiohiko whakaahua: te whakawhitiwhiti muka whatu, ngā pūoko tika, te ine mārama kua whakatikatikaina
– Ngā pūwhakaahua-whakawhiti: ngā pūoko mea, ngā pūoko raina, ngā hononga-whakaahua, ngā pana rama
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5. Ngā Tauira o ngā Whakamahinga i te Ao Tūturu
1. Ngā hononga whatu
He maha ngā optocouplers e whakamahi ana i ngā phototransistors nā te mea me nui te tohu putanga hei taraiwa i ngā ara iahiko mamati, ara iahiko whakawhiti rānei.
2. Kaiwhiwhi pūwero
I roto i ngā kaiwhiwhi IR (mamao), ka whakamahia pinepinetia ngā photodiode, ngā kōwae kaiwhiwhi IR rānei e hangai ana ki te photodiode me ngā whakakaha ā-roto, nā te mea me tere te urupare ki te whakarerekētanga (hei tauira, 38 kHz).
3. Pūoko raina i runga i te karetao
He maha ngā wā ka whakamahia ngā phototransistors me ngā IR LED hei tuku whakaata hei pānui i ngā whakaata mārama mai i ngā mata pango/mā.
4. Mita kaha mārama
He pai ake ngā photodiode mō ngā taputapu e hiahia ana kia tika te kaha me te rārangi.
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6. Whakamutunga
Ka hurihia e ngā photodiode me ngā phototransistors te mārama hei tohu hiko, engari he rerekē ngā huarahi e mahi ai rāua . Ka whakamahia e ngā photodiode te hanganga o ngā takirua irahiko-pōhatu i te hononga PN hei whakaputa i te iahiko whakaahua tere me te āhua rārangi, he mea pai mō ngā tono tere-tiketike me ngā inenga tika. I tētahi atu taha, ka whakamahia e ngā phototransistors ngā pānga o te mārama hei "whakakapi" i te iahiko turanga, kātahi ka whakanuia mā te whakanui o te transistor, ka nui ake te tairongo me te ngāwari ake te whakamahi i roto i ngā ara iahiko māmā, ahakoa he puhoi ake, he iti ake te rārangi.
Mā te mārama ki te mahi a ngā mea e rua, ka taea e tātou te whiriwhiri i ngā wāhanga tika mō ā tātou hiahia: ahakoa he tere me te tika (ngā photodiode) he aro me te ngāwari rānei (ngā phototransistors). Ina whakamahia tika, he tūāpapa nui ngā mea e rua mō ngā pūnaha pūoko whatu hou .
