Solar cells - working (and difference from photodiodes) | Semiconductors | Physics | Khan Academy

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  • Опубліковано 4 січ 2025

КОМЕНТАРІ • 130

  • @humanerror06
    @humanerror06 Рік тому +43

    One of the clearest explanations of the photovoltaic effect. Well done !!! Perfect for educatory purposes. Complete enough also for engineering level!

  • @charuprabha4534
    @charuprabha4534 4 роки тому +99

    U r amazing...,.,,..man u deserve million views ..

  • @arvindsrivastav8066
    @arvindsrivastav8066 4 роки тому +21

    I dont know why are you not having views .......everyone watching this Pleaseeeee!! share his viedos ...
    He is absolutely amazing

    • @krishnanand_ps
      @krishnanand_ps 2 роки тому +1

      bro this is khan academy, one of the biggest free education websites in the world

  • @petertomaszewski9058
    @petertomaszewski9058 3 роки тому +35

    Perfect presentation. Simplicity of reasoning behind explanaitions is exceptional. Best regards .

  • @AmitVerma-zl9et
    @AmitVerma-zl9et Рік тому +112

    Physics wala is far more overrated..U deserve applause

    • @anushkasrivastav4654
      @anushkasrivastav4654 11 місяців тому +11

      Stop comparing ffs...

    • @rohithenics
      @rohithenics 10 місяців тому +7

      Bhai compare hi krta rhega puri zindagi ?

    • @liyapathu-go7wi
      @liyapathu-go7wi 9 місяців тому +18

      Well , physics wallah aids students in cracking competitive exams. Their lectures , the time frame and covered topics are specific to the exam , with Pyqs & all. Meanwhile Khan academy provides quality education with these pocket lectures, that can be used by ALL, high school students, aspirants, engineers…everyone!. Khan academy sure is underrated though.

    • @GuruVikash-JeeAdv
      @GuruVikash-JeeAdv 3 місяці тому +1

      @@liyapathu-go7wi True ...

    • @achievedbigiasasi1333
      @achievedbigiasasi1333 2 місяці тому

      ​@@liyapathu-go7wi well said

  • @s.3421
    @s.3421 2 роки тому +3

    Guys I bet uh, u won't get a better video than this in the whole of the utube!!
    I wasted a lot of time,
    searching for a video where I could understand p n junction , rectifier,solarcells clearly...
    And then I found these videos where I understood it finally!!!
    Tqsm🙏🏻🙏🏻👏🏻👌🏻🥳🥳

  • @gameingplayer1352
    @gameingplayer1352 9 місяців тому +3

    Great video

  • @sadiomainmane829
    @sadiomainmane829 3 роки тому +13

    Thank you much sir for clearing the doubt as i earlier thought that light falling on depletion region provides nothing, even when i studied the Photodiode. But now i realized that the depletion region even it is free of any carriers but they do contain the crystal atoms(Si along with the doped atoms which are bounded) and the atoms(acceptor/donor)which are still there are referred to here as the immobile free ions

  • @faraz2609
    @faraz2609 2 роки тому +6

    6:13 I also had this confusion but your explanation helped me alot... thanks 😊

  • @divyanshkumarsrivastava3325
    @divyanshkumarsrivastava3325 3 місяці тому +3

    His name is Mahesh and he owns a channel Float Head Physics with even more beautiful content
    0:03

  • @revenger3006
    @revenger3006 11 місяців тому +2

    Bro why don't u have a million subscribers.....
    U should have atleast 10 million according to the content you are providing 🙂

  • @aswin8063
    @aswin8063 3 роки тому +2

    Now this is wat we call a legendary explanation

  • @debayanhalder7858
    @debayanhalder7858 4 роки тому +10

    Thank You soo much sir, Loved it ...
    Love khan Academy from India ...
    Jai Hind !

  • @A.venger_S
    @A.venger_S 2 роки тому +1

    You're voice and accent is so good and you explained it really well

  • @arvindsrivastav8066
    @arvindsrivastav8066 4 роки тому +5

    Sir You are an Amazing ! Teacher

  • @kaceesnow
    @kaceesnow 2 роки тому

    I never understood the concept until today Thanks. You're the Best

  • @Khan-xj9sp
    @Khan-xj9sp 4 роки тому +9

    Thankyou Very Much ❤️
    We want you to cover more chapters of class 12 please.
    All the lectures of 11th were available and it was easy for me but now I am said as class 12th chapters are still not published whether it's chemistry or physics :(

  • @chamanlaldewangan6591
    @chamanlaldewangan6591 8 місяців тому +1

    Thanks sir. I understand the photovoltaic effect.

  • @nehachoudhary672
    @nehachoudhary672 2 роки тому +2

    Thanks 😊👍

  • @Subhashree_Subudhi
    @Subhashree_Subudhi 6 місяців тому

    All possible confusions can be cleared over here... Thank you 🙏

  • @riya...125
    @riya...125 Рік тому

    You deserves millions of subscribers ❣️❣️

  • @adarshanilkumar.9197
    @adarshanilkumar.9197 Місяць тому

    bro its so clear and precise .

  • @reshmak.j1160
    @reshmak.j1160 2 місяці тому

    Amazing explanations

  • @prasenjeetfulmali6707
    @prasenjeetfulmali6707 2 роки тому +1

    Genuine explanation👍

  • @premasantosh8436
    @premasantosh8436 3 роки тому +2

    Thankyou so much. Your explanation was very simply put , hence understood very well. In fact the best video lecture on semiconductors available. Very grateful for this sir.

  • @klbpbw7eeoh
    @klbpbw7eeoh 2 роки тому +1

    Wow fantastic explanation thanks a lot

  • @neiltauro2234
    @neiltauro2234 10 місяців тому +1

    TOmm boards you helped me, thank you sir

  • @NkRai-hr8zf
    @NkRai-hr8zf 5 місяців тому

    I can't understand led , photodiode and solar cell by reputed institutes, but you make it clear bro😊

  • @juhisingh7654
    @juhisingh7654 2 роки тому +1

    Topic is clearly and wisely explained 👌

  • @03_angammeghadutsingha28
    @03_angammeghadutsingha28 2 роки тому +1

    I really like you bro..... What ever the topic you just make it simpler..💗💗... Wanna meet you someday

  • @sg627k
    @sg627k 2 роки тому +1

    Amazing explanation!

  • @MayankGoel447
    @MayankGoel447 4 роки тому +4

    Thank you for the semiconductor series Khan Academy. This helped me a lot

  • @cleanriver2
    @cleanriver2 Рік тому

    Best explanation I've seen!

  • @chemist7908
    @chemist7908 3 роки тому

    Best lecturer on Khan academy

  • @ajayxoxo
    @ajayxoxo 2 роки тому +1

    That is the difference between experienced teachers
    Thank you sir

  • @SudhanshuMishra-uk7pg
    @SudhanshuMishra-uk7pg Рік тому

    Amazing it is ❤....unbelievable explanation

  • @dr.lakshmimamilla9261
    @dr.lakshmimamilla9261 Рік тому

    Crystal clear explanation 👌 👏. Thank you somuch

  • @smrafiq7751
    @smrafiq7751 3 роки тому

    U teach effectively, very appreciating.

  • @shabbirahmad7015
    @shabbirahmad7015 2 роки тому

    YOU ARE A LIFESAVER

  • @diptijohn5058
    @diptijohn5058 11 місяців тому

    Thankyouu for such a nicee explanation❤❤

  • @sakethkashyapnagendra9278
    @sakethkashyapnagendra9278 2 роки тому +1

    Wonderfully explained ! Thanks a lot sir !!

  • @niranjan7457
    @niranjan7457 3 роки тому +2

    Sir, at 04:59, you mentioned that the electrons will start repelling each other and hence cause a current to flow in the circuit
    However, these repulsions would have been there all the time, right?
    But since we now attached wires, a path for the electrons to flow has been created and hence, after the repulsion, they start flowing in the wire, which wasn't possible previously (When there was no path/wire for the electrons to flow and these electrons were moving within the diode itself after repulsion).
    Am I right sir?

  • @sattwikindu6647
    @sattwikindu6647 3 роки тому +1

    amazing video. thanks for the great explanation

  • @배성준-z6s
    @배성준-z6s 2 роки тому +1

    I love 용제 ❤️

  • @shafqatilyas971
    @shafqatilyas971 Рік тому

    finally, I got the actual concept.

  • @zharaalipanahi8084
    @zharaalipanahi8084 2 роки тому

    Thanks 🙏🙏🙏🙏🙏🙏🙏🙏

  • @sarathvijayananda769
    @sarathvijayananda769 2 роки тому

    Thanks for simple and clear presentation.

  • @natureClipsHimalayan
    @natureClipsHimalayan Рік тому

    best explanation, thank you 👏👏

  • @hc8063
    @hc8063 3 роки тому

    Excellent teaching...Thank You.

  • @sewind6613
    @sewind6613 2 роки тому

    Excellent explanation. Thank you so much.

  • @shubhanksingh6918
    @shubhanksingh6918 2 роки тому +1

    lets say if Sir Issac newton would be watching you, then he would love this💗💗💗

    • @hellobro564
      @hellobro564 2 роки тому +1

      Newton doesn't know about semiconductors bruh

  • @dr.abdelmounaimchetoui
    @dr.abdelmounaimchetoui Рік тому

    very well explained. Good job

  • @rukeshveera5608
    @rukeshveera5608 2 роки тому

    Thanks❤ great 👏 explanation

  • @adityadivyasharma2969
    @adityadivyasharma2969 3 роки тому

    Thank you so much sir!!❤

  • @ganeshraja1789
    @ganeshraja1789 2 роки тому

    Simple and superb

  • @svnspell6709
    @svnspell6709 8 місяців тому +1

    Can someone explain,why is it in the photodiode the majority charge carriers in N type (electrons) dont flow through the battery and recombine with the holes in p type,when we reverse biase it? Why is it that only the pair which was formed through photon gets to go through the battery and recombine on the other side? This might be a dumb question but if someone can explain,please do:/

    • @athiramn
      @athiramn 6 місяців тому

      Those which are already in the material are bound charges, both holes and electrons. And if they manage to reach the space charge region, they will be swept away by the electric field present there. This is limited by the equilibrium process of diffusion and built in potential. The carriers generated when light falls upon the junction are excited electrons with a specific life time, those which are generated at one diffusion length from the junction are, thus, swept away through the external circuit.

  • @shaikjeelan4290
    @shaikjeelan4290 3 роки тому

    Loved a lot.Thank You Sir

  • @gauranshigupta9835
    @gauranshigupta9835 3 роки тому

    It's too good 👍👍

  • @niranjan7457
    @niranjan7457 3 роки тому +1

    Sir you mentioned that the idea of a solar cell is to let the charges accumulate. But at 05:02, as soon as a bulb is connected, these charges start flowing and recombination takes place, thereby causing accumulation to cease (as told in 06:55 -> electron hole pairs are swept and allowed to recombine thereby recombination doesn't take place)
    If allowing the charges to recombine prevents accumulation, then how do charges get accumulated in Solar cells, even if there's recombination taking place?

  • @shaikrafik6300
    @shaikrafik6300 4 роки тому +1

    Thanks GOD

  • @cryptocheeze
    @cryptocheeze 3 роки тому

    I wish i had seen this sooner❤

  • @pradroydip
    @pradroydip 8 місяців тому +1

    For a beginner it is okay, but that’s not a complete picture. There are so many concepts are missing, diffusion length for an instance. Formation of excitons within the diffusion length of the junction is critical for current collection.

    • @King-wp7yb
      @King-wp7yb 4 місяці тому

      I guess this is made for beginners,not for researchers

  • @Esihlebanga
    @Esihlebanga Рік тому

    You the best

  • @johnsumith2107
    @johnsumith2107 4 роки тому

    Sir please make lectures on structural analysis 🙏🙏🙏

  • @zoyanoor0039
    @zoyanoor0039 6 місяців тому

    I want clarification that with p side we connect positive electrode or negative electrode in solar cell ???

  • @aryavbhola3066
    @aryavbhola3066 3 роки тому +1

    In your breakdown voltage video. i think because with increase in voltage as V=E.d, d will increase making E constant because charges are mobile but when the deplesion region covers the entire diode, d cannot exceed and furthur increase ibn voltage will lead to increase in electric field which in turn will lead to breakdown voltage. the only difference between your explaination and mine is that E will remain constant at first

  • @riyagarai5805
    @riyagarai5805 2 роки тому

    Great

  • @kaviyak683
    @kaviyak683 2 роки тому +1

    Hi sir
    I need some clarification sir
    When Photon strike on depletion layer electron moves towards n side due to the hole (minority carrier)
    My question is
    In p side we have more holes than n side why electrons not moving towards p side?
    Kindly help me to clarify this

    • @hrid._.42o
      @hrid._.42o Рік тому

      Because of the strong polarity of depletion region

  • @jothibaskarn887
    @jothibaskarn887 Рік тому

    Very nice

  • @aryavbhola3066
    @aryavbhola3066 3 роки тому +1

    please tell why these electrons wont get finished. some point in time they, all electrons must get differentiated. and now if we attach a wire across diode's ends and then remove it it must take away all electrons from -ve to +ve side would merge releasing energy and everything will get ionised.

    • @shreyavijay715
      @shreyavijay715 3 роки тому

      I have this SAME exact doubt!

    • @gireeshbhat4158
      @gireeshbhat4158 3 роки тому +1

      😆😅 If you attach a wire across diode, from one side electrons are leaving (from negitive side p)
      From another side of wire (from positive side n)
      electrons are coming
      So number of electrons outgoing=number electrons incoming what happens only charges get recombined if there is a separation there is potential
      Now tell me how electrons get finished 🤔

  • @tonyfalapatt1308
    @tonyfalapatt1308 3 роки тому

    Thankyou🤩🤩🤩🤩🤩🤩🤩

  • @standarsh7895
    @standarsh7895 3 роки тому +1

    Sir, can the electron-hole pairs that are separated in the depletion layer run out? I don’t understand where the holes and electrons keep coming from.

    • @niranjan7457
      @niranjan7457 3 роки тому

      They are generated continuously because the light incident upon it, provides energy to the electrons, which get promoted to the higher energy level (this creates a free electron) and causes a hole to form (in the position where they had been initially before getting energy from the light)

  • @ANJA-mj1to
    @ANJA-mj1to Рік тому

    The topic of photovoltaics (or generating electricity directly from the sunlight) is a topic of growing interest to civil engineers as the integration of photovoltaic (PV) cell into the envelope of buildings (either as a well cladding system or as a roofing substitute) reduces the cost of building a PV power unit. This presentation 👌 is section to describe photovoltaic cell and photovoltaic cell to support structure-structure is provides FREE and electricity can be used on site or exported into the electricity grid from building.

  • @priyadharshini-px2vl
    @priyadharshini-px2vl 4 роки тому +1

    can you help me find the video for photodiode and LED. i very badly need it . thank you

    • @rajatverma3085
      @rajatverma3085 4 роки тому +1

      ua-cam.com/video/KgKcbW77txY/v-deo.html

  • @tejuniversal5872
    @tejuniversal5872 2 місяці тому

    I have one doubt about depletion region is that how the electron hole pair generated in electric field region is there any atoms between positive and negative ions, give me some clarity 🤔🤔

  • @niranjan7457
    @niranjan7457 3 роки тому +1

    Sir, at 05:10
    You mentioned that as recombination continues, new electron - hole pairs form
    What is the relation between recombination and formation of new electron - hole pairs? Because doesn't the formation of electron - hole pairs depend on the light supplied? I assume that as recombination takes place (And thereby, electron - hole pair gets destroyed), there is a "Room" formed for the new electron - hole pair. Am I right in my understanding sir?
    So, I have an understanding that There is no drop in voltage, because for every electron - hole pair that gets destroyed, a new electron - hole pairs gets generated in the depletion region, get pulled and replace the destroyed electron - hole pair. Am I right sir?

  • @ibtihajmujahid8206
    @ibtihajmujahid8206 Рік тому

    My question do they both hve drift current?

  • @puneetbansal2970
    @puneetbansal2970 2 місяці тому

    Why can't we simply connect bulb across the diode. Free electrons in N side will start flowing in outer circuit towards P side. Why do we need light?

  • @JACARTISTEOFFICIEL
    @JACARTISTEOFFICIEL 2 роки тому

    Amazing video! Wonderful ! Millions thanks !
    By the way I have a question. How can it be possible that electrons get generated for years? Won't it finish just after some little hours ?
    If we don't use voltage that appears, does electrons get accumulated again and again? Finally what will be the effect on the cell ?

  • @madhusudhany.v44
    @madhusudhany.v44 3 роки тому +1

    Sir,Why electrons move away towards corner instead of recombine with positive charge?you told it will swept away towards end due to electric field but why? However your explanation is best for my mindset because I always have doubts, questions just the way you explains. it's like you are answering exactly to my doubts, Thanks if possible clarify my doubt?

  • @vipyo489
    @vipyo489 3 роки тому

    Great!!! I have a question. If a cell is operating, electrons in depletion region will be decreased. Does 'life of solar cell' means losing enough electrons in depletion region that make the current?

  • @inshaaabid5310
    @inshaaabid5310 2 роки тому

    The fact is that what you call positive layer or negative layer are actually neutral charges then how can they conduct electricity.

  • @AnjeshKumar-l3s
    @AnjeshKumar-l3s 10 місяців тому

    you are telling there is no charge carrier in CB and VB but how photon eject electron from VB?

    • @my_oxyjin_bts_
      @my_oxyjin_bts_ 10 місяців тому

      Charge carriers do not lie in either cb or vb, but they are somewhere in between the two bands aren't they? Bonded electrons lie in the vb and free electrons in the cb

  • @niranjan7457
    @niranjan7457 3 роки тому +1

    Sir, one more doubt
    The only difference between solar cells and photodiodes is the voltage, right?
    And, can we use a photodiode for lighting up a bulb, because it can produce a current, right?

  • @vivekgudise3379
    @vivekgudise3379 3 роки тому

    Sir I do not find the photodiode video...

  • @cocothedon9063
    @cocothedon9063 2 місяці тому

    It is just like photocells

  • @prasantaghora8831
    @prasantaghora8831 4 роки тому

    @khanacademy Isn't current supposed to flow from left to right in photodiode? It'll be great if you explain.

    • @guts1303
      @guts1303 3 роки тому

      Yes current flows from left to right (opposite to flow of electrons and in the direction of the flow of holes)

  • @leavemealoneplease652
    @leavemealoneplease652 10 місяців тому

    This is called photovoltaic effects? Doesn’t it?
    1.What would happen if electron-hole pairs generate outside of depletion region?
    Because light is also falling over the semiconductor diodes.
    2. Does depletion layer increases(potential barriers increases) when it exposes to light?
    3.how P-N semiconductor is made with figure? Specially depletion region?
    4.light is exposed to the N-type semiconductor. In Practical, measures taken to increase the depletion layer by making N-types small in size compared to P-Type. ......
    5. When does diode work as forward biasing?
    Reverse biasing?
    6. Oh,yes now I get that. Why was Sir teaching us that how visible light carries out electrons from semiconductor in room temperature?
    "Just automatic electrons will get out of semiconductor(must be doped either N-type or P-type) when it is exposed to Light"

  • @satya4002
    @satya4002 2 роки тому

    There is no light ni space right! Then what is the use of sonar pannels in satelites ? Sir can you explain this

    • @mordecaichisata8131
      @mordecaichisata8131 3 місяці тому

      There is light in space, not just enough surfaces to reflect light on, that's why it seems dark in space.

  • @veeraentertainment5935
    @veeraentertainment5935 3 роки тому

    Wooooow🙏🙏🙏

  • @subhradipsandilya1469
    @subhradipsandilya1469 Рік тому

    I understand that due to theke concetration on electron in n side and holes in p side, in behaves like a cell and if we connect with a bulb, in will glow. But, in a normal PN diode also, n side has higher concentration of electron and p side has higher concentration holes, then why in doesnt behave like a cell? If we connect a bulb across a normal PN diode, why theke bulb doesnot glow like a solar cell? Kindly clear my doubt plz...thanks

  • @niranjan7457
    @niranjan7457 3 роки тому

    Sir another doubt...
    By shining light on the diode, we are creating electron - hole pairs. The electrons are pulled towards the N - type, while the holes are pulled towards the P - type
    And you mentioned that there is a voltage being created
    Is the voltage that is being created, in the depletion region (because holes that are generated in the depletion region, by photons, are pulled to the left and electrons that are generated in the depletion region, by photons, are pulled to the right, hence it appears as if there is a net current towards the left, in the depletion region), or outside it (because now that the holes have been pulled to the P type and electrons to the N type, where they are the major carriers respectively, doesn't it lead to an increase in the diffusion current [due to more availability of major charge carriers] which acts to the right) ?
    Kindly clarify sir..

  • @niranjan7457
    @niranjan7457 3 роки тому

    Sir,
    Can we summarize the difference between solar cells and photodiodes, by saying that we allowed the charges to accumulate in solar cells and then attached wires after some time (in the time gap, charges accumulated because the light was shining on it) and the recombination process started only after some time, while we didn't give any time for charges to accumulate in photodiodes because we almost immediately reverse biased it, hence the recombination process started immediately, thereby allowing almost no voltage. The time for which photons were incident upon the diode is the factor that decides whether it is going to be a photo diode or solar cell. Am I right sir?

  • @emohmomomo
    @emohmomomo 2 роки тому

    Solar cells are not biased right?

  • @yoanshie
    @yoanshie 2 роки тому

    They should provide notes damn

  • @grdharshann9014
    @grdharshann9014 Місяць тому +1

    in 2024 november

  • @dhruvitapatel7282
    @dhruvitapatel7282 2 роки тому

    👌🏻👍

  • @vishalgi4821
    @vishalgi4821 3 роки тому +1

    Hindi bhi bol do

  • @thecerebrum.
    @thecerebrum. Рік тому

    Awesome. A suggestion, please don’t imitate an accent if not natural, it’s bugging for some. No offense.

  • @AyushNishad
    @AyushNishad 2 роки тому

    1.25x speed ans thank me later