Kumumanaʻo Hana o nā Photodiodes a me nā Phototransistors
ʻO ka hoʻomohala ʻana o ka ʻenehana uila hou e hilinaʻi nui ʻia i nā mea ʻike i hiki ke "ʻike" i ka mālamalama a hoʻololi iā ia i mau hōʻailona uila. ʻO nā ʻāpana ʻelua i hoʻohana nui ʻia no kēia kumu, ʻo ia nā photodiodes a me nā phototransistors. No ka ʻohana o nā semiconductors mālamalama-sensitive lāua ʻelua, i hoʻohana nui ʻia i nā ʻōnaehana automation, nā kamaʻilio optical, nā mea ana , a me nā mea hoʻohana e like me nā mana mamao, nā mīkini paʻi, a me nā mea ʻike kukui i nā kelepona paʻalima. ʻOiai ʻelua e pane i ka mālamalama, he ʻokoʻa nā loina hana, nā ʻano, a me nā noi o nā photodiodes a me nā phototransistors. Kūkākūkā kēia ʻatikala i kā lākou mau loina hana ma ka hohonu, e hoʻohālikelike ana iā lākou, a e hāʻawi ana i nā laʻana o kā lākou noi.
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1. Nā kumu o ka ʻike ʻana i ka mālamalama i nā Semiconductors
I mea e hoʻomaopopo ai i nā photodiodes a me nā phototransistors, pono mākou e hoʻomanaʻo i ke kumumanaʻo koʻikoʻi o nā semiconductors: nā mea lawe ukana, nā electrons a me nā lua. Ke paʻi ka mālamalama (photons) i kahi mea semiconductor, hoʻoikaika lākou i nā electrons, e neʻe ai lākou mai ka valence band a i ka conduction band. Hoʻokumu kēia kaʻina hana i nā hui electron-hole. ʻO ka nui o nā photons i omo ʻia, ʻoi aku ka nui o nā hui mea lawe ukana i hoʻokumu ʻia, e hoʻonui ana i ka nui o ke au e hiki ke kahe.
ʻO ke kumu nui: hoʻāla ke kukui i nā loli i nā waiwai uila o nā ʻāpana. Hiki i kēia mau loli ke ʻano o ka piʻi ʻana o ke au, ka emi ʻana o ke kū'ē, a i ʻole ke ʻano o ka voltage. I loko o nā photodiodes a me nā phototransistors, ʻike ʻia ka loli mua i ke au.
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2. Kumumanaʻo Hana o ka Photodiode
a. ʻAno a me ke ʻano o ka hana
ʻO ka photodiode he diode PN (a i ʻole nā ʻano like ʻole e like me PIN a me nā photodiodes avalanche) i hoʻolālā ʻia e ʻike i ka mālamalama. Hoʻokumu ka ʻano PN i kahi ʻāpana depletion, kahi ʻāpana i nele i nā mea lawe uku manuahi e hana ana e like me kahi "wahi hoʻokaʻawale" i hoʻopiʻi ʻia.
Hiki i nā Photodiodes ke hana i nā ʻano hana like ʻole, akā ʻo nā mea i hoʻohana pinepine ʻia:
1. ʻAno hoʻokele kiʻi (hoʻohuli i ka manaʻo)
Hoʻohuli ʻia ke ʻano o ka photodiode. Hoʻonui ʻia ka ʻāpana depletion, wikiwiki ka pane ʻana, emi ka capacitance, a maikaʻi ka linearity. He mea maʻamau kēia ʻano no nā sensor a me nā kamaʻilio optical.
2. ʻAno Photovoltaic (ʻaʻohe bias/ʻaʻohe bias)
ʻAʻole pili waho nā Photodiodes. Hoʻopuka ka mālamalama e komo mai ana i kahi volta e like me kahi cell solar, ʻoiai he liʻiliʻi. Loaʻa i kēia ka maikaʻi o ka walaʻau haʻahaʻa, e kūpono ai no kekahi mau ana, akā hiki ke lohi ka pane ma mua o ka bias reverse.
b. Ke ʻano hana o ka hoʻololi ʻana i ka mālamalama i ke au
Ke hōʻike ʻia ka photodiode i ka mālamalama:
1. Hoʻopili ʻia nā photons ma ka ʻāpana depletion a kokoke paha i ka hui ʻana.
2. Hoʻokumu ʻia kahi hui electron-hole.
3. Kahua uila ʻO ke kūloko ma ka hui ʻana e hoʻokaʻawale i ka pālua:
– Ua paʻi ʻia nā electrons i ka ʻaoʻao N
– Ua paʻi ʻia ka lua i ka ʻaoʻao P
4. Hoʻopuka kēia hoʻokaʻawale ʻana i ka uku i kahi photocurrent.
ʻO ka holoʻokoʻa holoʻokoʻa he hui pū ʻana o:
– Au pōʻeleʻele: he au liʻiliʻi e kahe ana me ka ʻole o ka mālamalama (ma muli o nā hopena wela).
– Ke au kiʻi: ke au e kūlike ana me ka ikaika o ka mālamalama.
I nā huaʻōlelo maʻalahi, ʻo ka ʻoi aku ka mālamalama o ke kukui → ʻoi aku ka nui o ke kahe kiʻi.
c. Nā ʻano o nā Photodiodes
ʻO kekahi mau hiʻohiʻona koʻikoʻi o nā photodiodes:
– Pane wikiwiki (kūpono no nā hōʻailona alapine kiʻekiʻe)
– Ka ikaika laina a i ka ikaika mālamalama ma luna o kekahi laulā
– He liʻiliʻi iki ke au hoʻopuka i hoʻohālikelike ʻia me ka phototransistor, no laila e koi pinepine ʻia kahi amplifier (op-amp/transimpedance amplifier)
– He mau mea nui ka walaʻau a me ke au ʻeleʻele i nā noi kikoʻī.
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3. Kumumanaʻo Hana o ka Phototransistor
a. ʻAno Kumu o kahi Phototransistor
ʻO ka phototransistor he transistor BJT (ʻo ka maʻamau NPN) nona ke kumu i hana ʻia i ka mālamalama. I loko o kahi phototransistor, hana ka mālamalama ma ke ʻano he "kumu kumu" e kaohi ana i ke au o ka mea hōʻiliʻili-emitter.
ʻAʻole e like me nā photodiodes, ka mea e hoʻopuka pololei i ke au mai ka hopena photon, hoʻohana nā phototransistors i ka loaʻa o ka transistor. Ma muli o ka loaʻa, hiki i ke au hoʻopuka o ka phototransistor ke nui aʻe.
b. ʻAno Hana: Mālamalama ma ke ʻano he Pani no ke Au Kumu
Hiki ke wehewehe ʻia pehea e hana ai penei:
1. Pā ka mālamalama i ka ʻāpana kumu-mea hōʻiliʻili (ʻo ka hui BC maʻamau).
2. Hoʻokumu ʻia nā hui electron-hole ma muli o ka omo ʻana o ka photon.
3. Hoʻopuka kēia hopena i kahi au liʻiliʻi e like me ke au kumu kiʻi.
4. I loko o kahi transistor BJT, ʻo ke au o ka mea hōʻiliʻili ma kahi o:
\[
I_C \approx \beta \cdot I_B
\]
ʻOiai ʻo \( I_B \) "hana ʻia" e ka mālamalama, na ka mālamalama e hoʻomalu iā \( I_C \).
ʻO ka hopena, hiki i nā loli liʻiliʻi i ka ikaika o ka mālamalama ke hana i nā loli nui aʻe i ke au o ka mea hōʻiliʻili ma mua o ka photodiode, ma muli o ka mea loaʻa \(\beta\).
c. ʻAno Kaapuni a me ka Hoʻokō ʻana
Hoʻohana pinepine ʻia nā Phototransistors i nā ʻano hana aʻe:
– Mea hoʻoheheʻe maʻamau: ka mea hōʻiliʻili i ka uila ma o kahi resistor, hoʻopuka ma ka mea hōʻiliʻili. Ke hōʻike ʻia i ka mālamalama, ʻoi aku ka "ON" o ka transistor, loli ka uila hoʻopuka.
– ʻO ka mea hōʻiliʻili maʻamau (mea hahai emitter): ka hoʻopuka ma ka emitter, pono no kekahi mau mea akā ʻaʻole i maʻamau i nā mea ʻike maʻalahi.
I kekahi manawa ua wehe ʻia ke pine kumu o nā phototransistors (3-pin), akā he nui nō hoʻi he 2-pin wale nō (ʻaʻole hiki ke komo i ke kumu kūloko).
d. Nā ʻano o nā Phototransistors
– ʻOi aku ka maʻalahi (ʻoi aku ka nui o ke au hoʻopuka)
- ʻOi aku ka lohi ma mua o nā photodiodes ma muli o ke kaʻina hana mālama ukana a me nā dynamics transistor
– ʻAʻole ia e linear ma lalo o kekahi mau kūlana, ʻoi aku hoʻi kokoke i ka saturation
– Kūpono no ka ʻike ʻana i ka mālamalama/pouli, ka ʻike ʻana i nā mea, nā optocouplers, nā helu hoʻohuli, a me nā noi kaohi maʻalahi.
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4. Hoʻohālikelike o Photodiode vs Phototransistor
Eia kahi hōʻuluʻulu manaʻo o nā ʻokoʻa nui:
1. Ka wikiwiki o ka pane ʻana
– Photodiode: wikiwiki loa (maikaʻi no nā kamaʻilio optical, modulation wikiwiki)
– Phototransistor: lohi (lawa no nā mea ʻike maʻamau)
2. ʻIke / hoʻonui
– Photodiode: au liʻiliʻi, koi pinepine ʻia ka hoʻonui ʻana
– Phototransistor: ke au nui ma muli o ka loaʻa ʻana o ka transistor
3. Ka Laina
– Nā Photodiode: ʻoi aku ka linear ma ke ʻano laulā
– Phototransistor: hiki ke nonlinear, maʻalahi ka saturated
4. Moʻo
– Photodiode: koi pinepine i kahi kaapuni hoʻonui au-a-voltage
– Phototransistor: hiki ke hoʻohana pololei ʻia me kahi resistor ukana maʻalahi
5. Noi
– Nā Photodiodes: kamaʻilio fiber optic, nā mea ʻike pololei, ke ana ʻana o ka mālamalama i hoʻoponopono ʻia
– Nā Phototransistors: nā mea ʻike mea, nā mea ʻike laina, nā optocouplers, nā kuapo kukui
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5. Nā Laʻana o nā Hoʻohana ma ke Ola Maoli
1. Mea hoʻopili maka
Hoʻohana ka nui o nā optocouplers i nā phototransistors no ka mea pono ka hōʻailona hoʻopuka e lawa ka nui e hoʻokele i nā kaapuni kikohoʻe a i ʻole nā kaapuni hoʻololi.
2. Mea hoʻokipa infrared
I loko o nā mea loaʻa IR (nā mea mamao), hoʻohana pinepine ʻia nā photodiodes a i ʻole nā modula mea loaʻa IR e pili ana i ka photodiode me nā amplifiers kūloko no ka mea pono lākou i kahi pane wikiwiki i ka modulation (e.g. 38 kHz).
3. Mea ʻike laina ma ka lopako
Hoʻohana pinepine ʻia nā phototransistors me nā IR LED e like me nā transmitters e heluhelu i nā ʻōlinolino kukui mai nā ʻili ʻeleʻele/keʻokeʻo.
4. Ka mika o ka ikaika o ke kukui
ʻOi aku ka kūpono o nā Photodiodes no nā mea hana e koi ana i ka pololei o ka ikaika a me ka linearity.
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6. Manaʻo
Hoʻololi nā Photodiodes a me nā phototransistors i ka mālamalama i nā hōʻailona uila, akā hana lākou me ka hoʻohana ʻana i nā ʻano hana like ʻole. Hoʻohana nā Photodiodes i ka hoʻokumu ʻana o nā hui electron-hole ma ka PN junction e hana i kahi photocurrent wikiwiki a linear, e kūpono ai lākou no nā noi wikiwiki a me nā ana pololei. Ma ka ʻaoʻao ʻē aʻe, hoʻohana nā Phototransistors i nā hopena o ka mālamalama e "pani" i ke au kumu a laila hoʻonui iā ia ma o ka loaʻa o ka transistor, e ʻoi aku ka maʻalahi o ka hoʻohana ʻana i nā kaapuni maʻalahi, ʻoiai ʻoi aku ka lohi a emi ka linear.
Ma ka hoʻomaopopo ʻana i ke ʻano o ka hana ʻana o nā mea ʻelua, hiki iā mākou ke koho i nā ʻāpana kūpono no kā mākou mau pono: inā paha mākou e ʻimi nei i ka wikiwiki a me ka pololei (photodiodes) a i ʻole ka ʻike a me ka maʻalahi (phototransistors). Ke hoʻohana pono ʻia, ʻo nā mea ʻelua he mau kumu koʻikoʻi o nā ʻōnaehana sensor optical hou .
