Photodiodes - (working & why it's reverse biased) | Semiconductors | Physics | Khan Academy

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  • Опубликовано: 26 янв 2025

Комментарии • 137

  • @personanongrata8690
    @personanongrata8690 4 года назад +111

    The content is amazing and your accent makes it 10 times better! This is the very first time I am finding physics interesting! Thanks

    • @Ivan0001
      @Ivan0001 2 года назад +1

      *electronics

    • @adeebahmed1067
      @adeebahmed1067 2 года назад +6

      @@Ivan0001 its a part of a chapter in physics genius!

    • @xlr8_bs514
      @xlr8_bs514 2 месяца назад +1

      @@Ivan0001 Electronics is a part of Physics, Einstein.

  • @AJ-td1sb
    @AJ-td1sb 2 года назад +50

    I'm currently doing an electrical engineering course. I mute the lecturer to listen to your explanation instead. Terrible isn't it. But thanks very much for putting these up.

  • @andreadanniballe5013
    @andreadanniballe5013 3 года назад +55

    Couldn't find a better explanation than this one, simply brilliant! God bless you and thank you so much!

  • @divyamkumarpandey7749
    @divyamkumarpandey7749 4 года назад +27

    Please add this video to the semiconductors playlist

  • @arushigautam2062
    @arushigautam2062 2 года назад +11

    Worth appreciating content...
    Cleared my concepts in one go😄

  • @mariammano1348
    @mariammano1348 2 года назад +11

    You just nailed it man! Hats off you 🥰 you just make me satisfy about this topic

  • @sunilchandradas1472
    @sunilchandradas1472 Месяц назад +1

    your explaination is just like wow .and your words make it more easier

  • @najeebqureshi3000
    @najeebqureshi3000 2 года назад +3

    Tomorrow is exam of 8th semester Thank you Sir ji! you cleared my concepts even my professor could not clear the concepts in the timeframe of 6 months you did it in 11:39 minutes.
    What a Legend!
    Lots of Love from Pakistan!

  • @ShaunFMichael
    @ShaunFMichael 4 года назад +9

    Couple of hours reading universities texts and nope. watch this video twice, plus the previous one and got it. Online universities (and brick) are so behind in teaching.

  • @amanbishtxiia3647
    @amanbishtxiia3647 4 года назад +12

    The content is really good 👍

  • @spurti
    @spurti 2 года назад +5

    Ohh the electrons from the negative terminal (electron flow) fills out the holes in p type material. Conversely the electrons from the n type side is reaching towards the positive terminal of the battery so the depletion layer is increased and if we finished this process then the current would not flow in a reverse bias mode.

    • @atomicreactions9201
      @atomicreactions9201 2 года назад +1

      Exactly. I am learning this topic a the moment, and he confused me lot, that he is doing it the other way arount.

    • @atomicreactions9201
      @atomicreactions9201 2 года назад

      Oh never mind. I was wrong my self. Because of the charge double layer, which results out of the will of the to potentials to get equivalent, the electrons forming on the p-side are directe moving to the n-side because the first space on the n-side is positivly charged.
      The result in the end is a potenzial difference and a resulting current.

    • @spurti
      @spurti 2 года назад +1

      @@atomicreactions9201 are you talking about reverse or forward bias mode?? Like I would recommend you to watch a video on diodes by ochem tutor on youtube. So that you get the basic concept and come back here and watch solar cells,photodiode and led.

  • @santhoshkumarb2408
    @santhoshkumarb2408 Год назад +2

    God sent this man 😅 for us guys !

  • @gabrielaportillo299
    @gabrielaportillo299 3 года назад +1

    I had no idea this was a khan academy video! this is amazing!

  • @manikantaboddu2197
    @manikantaboddu2197 2 года назад +2

    Very useful stuff for engineering students... Thank u soo much sir :)

  • @niranjan7457
    @niranjan7457 3 года назад +14

    Sir at 07:43
    You mentioned that we want the current only due to light so we don't use forward biasing (as another current flows)
    But in reverse biasing, a current flows (not due to photons) but it's very small. So we are neglecting that current, right?

    • @radhakrishnajha5084
      @radhakrishnajha5084 3 года назад +2

      Ofcourse

    • @avijitmudgal7554
      @avijitmudgal7554 3 года назад +2

      Off course...see the current generated in the depletion layer is enormously small as compared to the current which is generated by light.

    • @debarshidas8596
      @debarshidas8596 2 года назад +1

      No, I think it is included in dark current

    • @semprocarnage
      @semprocarnage Год назад

      ​@@debarshidas8596ya

  • @sambhavchaudhary6344
    @sambhavchaudhary6344 2 года назад +3

    great explanation

  • @DeepakSingh-yy1vn
    @DeepakSingh-yy1vn 4 года назад +7

    Sir ossmmmmm content 🤗🤗🤗. I love the way u teach....
    Sir it's a rqst pls upload solar cell as tomorrow is my pre exam of phy

  • @raghumandati463
    @raghumandati463 4 года назад +3

    Content is ever good

  • @missarcane-uy1mt
    @missarcane-uy1mt Год назад

    idk how to thank u , really amazed by ur teaching

  • @manishasharma6730
    @manishasharma6730 Год назад

    Excellent, this video created my interest in physics....

  • @akhilseelam3741
    @akhilseelam3741 7 месяцев назад

    00:02 Photodiodes convert light to electricity and are used in detecting brightness
    01:39 Reverse biasing in photodiodes limits current and widens depletion region.
    03:08 Light absorption in semiconductors creates electron-hole pairs
    04:32 Light absorption generates current in semiconductors
    06:01 Photodiodes detect brightness using reverse bias.
    07:27 Photodiodes work in reverse bias to ensure current is only due to light.
    08:54 Current generated by photodiodes is independent of voltage after a certain point due to the number of electron-hole pairs formed by the light.
    10:15 Photodiodes can generate a tiny current even in absence of light due to thermal energy.

  • @alonzoball6266
    @alonzoball6266 11 месяцев назад

    You made incredible sense than my lecturer and he has one more than an hour video on this and still doesn't make any sense.

  • @zauletandrei
    @zauletandrei 3 месяца назад

    this is the best explanation i found

  • @AkshayKumar-lx5cr
    @AkshayKumar-lx5cr 2 года назад +1

    Amazing explanation. This is gonna make my day

  • @runzit2007
    @runzit2007 4 года назад +3

    Excellent

  • @karlberggren2042
    @karlberggren2042 3 года назад +7

    Nice video. My only suggestion is that the i v curve should not go to the origin. Even at v=0 you should see significant photo current, I believe.

    • @lewtube6436
      @lewtube6436 Год назад

      I agree -- because the depletion region is still present at v = 0 (albeit a non-expanded one), and it's in this region the current is generated.

  • @yashbehl8807
    @yashbehl8807 3 года назад +1

    Amazing, regenerated my interest in the subject.

  • @ashleymariamthomas1120
    @ashleymariamthomas1120 Год назад +1

    Thank you so much for the detailed explanation 😊

  • @techrajix
    @techrajix Год назад

    It was a great explanation sir

  • @armaan7194
    @armaan7194 Год назад +1

    You are really a very good teacher... Ur videos are so knowledgeable and time saving👍🏻

  • @advanceringnewholder
    @advanceringnewholder 2 года назад

    thanks man, you have answered my questions.

  • @amanuelabbittee4511
    @amanuelabbittee4511 8 месяцев назад

    God bless you, man❤❤❤

  • @srujan797
    @srujan797 Год назад

    Crystal clear sir ❤❤

  • @zraarali4323
    @zraarali4323 Год назад

    No one can beat these lctrs for sure of khn acdmyy for thiss chpp🤓

  • @jinny8014
    @jinny8014 2 года назад

    Thank you for making this easier

  • @alv9
    @alv9 5 месяцев назад

    Very helpful! Thank you very much!

  • @umabagri2848
    @umabagri2848 3 года назад +11

    Even if Issac Newton, Albert Einstein would watch you, they would love your way of teaching. ❤❤❤❤❤❤❤

  • @08athakwaninandish16
    @08athakwaninandish16 3 года назад +2

    विवरण और ग्राफिक्स, दोनों ही बहुत अच्छे हैं।
    Hats off to you dude and to Khan academy!!!

  • @khuuus5994
    @khuuus5994 2 года назад

    Animations are best source of studies💘

  • @josecarlosferreira4942
    @josecarlosferreira4942 2 года назад

    This guy is brilliant. Thank you sir!

  • @vershitayadav7753
    @vershitayadav7753 2 года назад +1

    love your teachings sir
    and your software as well

  • @ruperthowton5091
    @ruperthowton5091 3 года назад +1

    Nice explanation thanks

  • @rippking3167
    @rippking3167 2 года назад

    veryyy well ilustrated and well comented!! thanks!

  • @soulmantrajee6683
    @soulmantrajee6683 2 года назад

    Nice way of explaining thinks👍🏻

  • @TwistedKrizZ33
    @TwistedKrizZ33 Год назад +1

    The best best one

  • @anamikapratiyush7364
    @anamikapratiyush7364 7 месяцев назад

    Excellent explanation, however the bossing in forward condition is not correct

  • @JJHanna
    @JJHanna 2 года назад

    Stellar explanation

  • @rakeshkulkarni4323
    @rakeshkulkarni4323 2 года назад

    Logical explanation

  • @sm-pz8er
    @sm-pz8er Год назад

    Thanks for the video. Why the current is from right to left not left to right? toward N junction?

  • @raw_penguin2316
    @raw_penguin2316 Год назад

    Great Video!

  • @prashantgiri2082
    @prashantgiri2082 11 месяцев назад

    Suppose if the light brightness is maximum, then will the current flow or the depletion region will blast...???

  • @qzorn4440
    @qzorn4440 3 года назад +1

    is the current flow direction due to the electron movement or the void of an electron hole movement as an electron in a vacuum???

  • @SD-mc9xm
    @SD-mc9xm Год назад

    The electron absorbing the energy from the photon sounds like the photoelectric effect

  • @samikshachauhan6078
    @samikshachauhan6078 Год назад

    Is this same happen in pin photodiode

  • @jigyasaagarwal6161
    @jigyasaagarwal6161 2 года назад

    Can you tell me the reason of negative current ??

  • @lumiluppy8294
    @lumiluppy8294 Год назад

    Hi! What do you mean add a diffuser in photodiode?

  • @TekCroach
    @TekCroach 4 месяца назад

    The bank note counter example... is that the way it really works? I don't think so. anyway, a very good explanation on the photodiode. thanks.

  • @heyyounotyouyou3761
    @heyyounotyouyou3761 Год назад

    Man this video was frinking awesome

  • @tasneem6427
    @tasneem6427 3 года назад +5

    Goddamn! This is so good 😳

  • @oyster4545
    @oyster4545 2 года назад

    How much lovely voice he has🥰😅

  • @olmusic7856
    @olmusic7856 2 года назад +1

    Tnx a lot

  • @javeriahfahim882
    @javeriahfahim882 2 года назад

    Best explanation

  • @vedgr8605
    @vedgr8605 2 года назад

    thanks a lot for these videos

  • @mwerensteijn
    @mwerensteijn 2 года назад

    Thank you so much!

  • @xpanda7112
    @xpanda7112 9 месяцев назад

    thank you very much

  • @beartheburn3863
    @beartheburn3863 4 года назад +1

    Shouldn't be the positive ion of the depletion region be containing the holes ?? 5: 22

  • @aramugamselvavadivel5262
    @aramugamselvavadivel5262 9 месяцев назад

    what software are you using to explain

  • @redhoodiestudio
    @redhoodiestudio Год назад

    It makes no sense to me that the free electron would recombine outside of the depletion region, because we apply an electric field with our reverse bias. Or what do I see wrong?

  • @surbhiparey2368
    @surbhiparey2368 3 года назад +1

    Amazing!

  • @khadijakaeedbhinderwala6502
    @khadijakaeedbhinderwala6502 2 года назад

    Awesome video

  • @aakashdewangan7313
    @aakashdewangan7313 2 года назад

    excellent!

  • @lowisakinson8628
    @lowisakinson8628 3 года назад

    Thanks alot sir

  • @raphaelcardoso7927
    @raphaelcardoso7927 3 года назад

    Very good explanation

  • @kartikchauhan8939
    @kartikchauhan8939 3 года назад

    Great work

  • @jyothi9151
    @jyothi9151 3 года назад

    the bestt💯

  • @Chillandrelax2475
    @Chillandrelax2475 2 года назад

    Hi, how to calculate a resistor value for a photodiode?

  • @jothibaskarn887
    @jothibaskarn887 Год назад

    Very nice

  • @sowndaryaravi5285
    @sowndaryaravi5285 3 года назад

    Very useful

  • @ojaspatil2094
    @ojaspatil2094 2 года назад

    beautiful

  • @ameeliamajid8140
    @ameeliamajid8140 3 года назад

    thanks!

  • @sbbarath5802
    @sbbarath5802 4 года назад +2

    can this be used in automatic doors which open when we go near it??????

    • @tasneem6427
      @tasneem6427 3 года назад

      We are not light emitting bodies. So I don’t think so 👀

    • @deepanshu564
      @deepanshu564 3 года назад

      infra-radiation detection is used in heat cameras for automatic doors

    • @Pushed2InsanityYT
      @Pushed2InsanityYT 3 года назад

      Possibly if you have some bright light shining at the sensor and you happen to block that light when you come near the door, current will decrease, and door can open, but I think this can raise many false alarms. Like what if a fly just cover up the sensor, or something.

  • @vivekthumu8992
    @vivekthumu8992 3 года назад +1

    I get answer for. my childhood question how bank. machine counts bundles of money in just seconds

  • @nomanaziz804
    @nomanaziz804 11 месяцев назад

    Love from Pakistan ❤

  • @petermarsh4993
    @petermarsh4993 2 года назад

    Dear Sir, I have a problem which you may be able to help me solve. I have a new Solar Panel installation and I want to use it in part to heat my underfloor heating through the electrical conduction wires embedded in my concrete floor. The problem is, when sunlight dims during the day, electricity comes from the grid to maintain a consistent flow of electricity to heat my floor. Grid electricity is expensive and I NEVER want to use grid electricity to heat the floor, only solar derived electricity.
    I was thinking of combining two devices to make a switch that turned on the output to the floor from my solar panels when the sun is shining and turn off current when the sun is not shining. The thought was to use a Photodiode as the current switch that is connected via a low voltage power supply to a solenoid. This solenoid switches off 240V power to my underfloor heating when the solar radiation {and therefore current in the low voltage circuit} drops to below a certain level and stops power going to the heater circuit. If the sun reappears from behind a cloud, the circuit goes back on again.
    What do you think about my problem and do you have any suggestions? Thanks.

  • @waleedgamerff3079
    @waleedgamerff3079 11 месяцев назад

    Waàoo❤❤❤

  • @crazystories-z1g
    @crazystories-z1g 3 года назад

    thanks sir

  • @seazaachannel1307
    @seazaachannel1307 3 года назад

    I want thaisub.

  • @parmanmshaibani8784
    @parmanmshaibani8784 3 года назад

    Best content in this term

  • @Kubolich
    @Kubolich 2 месяца назад

    Why did you redeeem it ah voice

    • @slickysaturn7243
      @slickysaturn7243 2 месяца назад

      you're American right?

    • @Kubolich
      @Kubolich 2 месяца назад

      @@slickysaturn7243 nope :)

    • @slickysaturn7243
      @slickysaturn7243 2 месяца назад

      @@Kubolich well then you have no excuse for being stupid, if you're here to study maybe actually study

  • @KaranKaran-fw1bt
    @KaranKaran-fw1bt 2 года назад

    Tomorrow tell it

  • @rishabhsamarwal573
    @rishabhsamarwal573 2 года назад +4

    Sir if you will teach this in hindi then your growth will become 10x

    • @siddharth8526
      @siddharth8526 2 года назад +1

      The heck bro, the only few channels that post teaching videos other than Hindi in India. This channel is for indians not for North Indians alone so shut up😡🤬🤬🤬🤬🤬🤬🤬

    • @aditi9069
      @aditi9069 2 года назад

      @@siddharth8526 exactly!

  • @devendra2003
    @devendra2003 2 года назад +1

    tum bhagwan ho 💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐💐👌👌💐💐🎂🎂🎂🎂💐💐👌💐💐🎂🎂🎂🎂💐💐💐💐77👌👍😢😊☺️☺️

  • @DeuryMota
    @DeuryMota Год назад

    Yess

  • @penumalasunitha14
    @penumalasunitha14 3 года назад

    Sir, what are used in Solar panels, photodiode or solar cells???

  • @sohamjadhav5218
    @sohamjadhav5218 2 года назад

    he sounds like @sauraXD

  • @va11bhav_rana
    @va11bhav_rana 3 года назад

    best

  • @yashboss9593
    @yashboss9593 2 года назад +1

    👍👍👍👍👍

  • @saju2385
    @saju2385 2 года назад

    Anna sivanesh anna

  • @Divyaskittens
    @Divyaskittens 10 дней назад +1

    Accent 😂

  • @safalgupta6927
    @safalgupta6927 4 года назад

    Golduuuu