The PN Junction. How Diodes Work? (English version)

The PN Junction. Developed under Teaching Innovation Project 11-293 of Universidad de Granada (Spain)
Creative Commons By-NonCommercial-NonDerivs.
English version.
All the themes in the soundtrack were released under Creative Commons licenses by their respective authors.
Soundtrack:
www.yasnayamusic.ru
www.chillcarrier.de
kammerer.jamendo.net
www.marknine.com
music.tunguskagrooves.com

[@thescottguy]

This is the most professional, well, animated, and well explained educational video I have ever seen on a scientific topic on the Internet. Good work.

[@fmgomezcampos]

+thescottguy Wow, thanks a lot!

[@theor4800]

+fmgomezcampos it's true

[@legendary_igel_master]

+thescottguy Although I do find the voice somewhat annoying (no offense) :/

[@ve2zzz]

By far the best PN junction explanation i've never seen....

[@ameermuhammad5129]

Oh thanks a lot! I spent the last three hours trying to understand this, now I did in ten minutes

[@minhokim8263]

Wonderful video! It explains much better than could I who have been working as an electrical engineer for 3 decades.

[@acur-un8xq]

Great video. You summed up 2 weeks worth of lectures in 10 minutes. Thanks

[@pdcx]

1000% clear than my lecture

[@randyliu8429]

Tyy

[@maresfillies6041]

God Bless, whoever created this. You saved this engineering student's butt. :D

[@fmgomezcampos]

Thank you for your lovely comment! :-D There is also available a Spanish version of this video :-D

[@gabehopper701]

I'm not an electrician out an electrical engineer. I've only had basic chemistry courses. Even with my limited background, this video did an incredible job of explaining how diodes work. Thanks for helping me continue my efforts to understand life, the universe, and everything.

[@gabehopper701]

One question. Why is it correct to visualize a current making the barrier higher or lower instead of visualizing it as increasing or decreasing the "pressure" of the electrons trying to flow "uphill?"

[@musedpony8939]

Gabe Hopper Hm, interesting question. Every analogy breaks down, and I think the 'uphill' analogy does here. The application of an external voltage increases the difference in electrical potential energy between n and p, providing the electrons with more energy so they can overcome the opposing difference in electrical potential induced by the dopants' relative charges. However, as the electrons overcome this barrier and begin flowing, the opposing dopant-induced voltage will consequently lower - and as this opposing voltage lowers, the electrons flow more readily. It's a feedback loop that reaches an equilibrium. These events happen so quickly that considering either the barrier being lowered or the electrons being given more energy as the initiator is of negligible difference, but perhaps it's more technically correct to think of the electrons as gaining more energy THEN the barrier lowers, and then the feedback continues until an equilibrium is reached.

[@fmgomezcampos]

Some days ago the user John Smith (I think) made a comment that I have unintentionally deleted. He mentioned that in a part of the video it is said that P impurities are negatively charged, but in another part of the video it is said that P parts of the device are positively charged. The answer is that P impurities are negatively charged when they accept an electron (releasing a hole in the process), so electrical neutrality still holds after this process. In consequence, free carriers in P doped regions are holes, positive charges, and P impurities (not free carriers) are negatively charged. I hope this helps.

[@sandraramirez7453]

jjjcuxzuf

[@ajlwhite]

A simple analogy is if you have a pipe full of water with a small bubble, it is much easier to think of the bubble as moving through the water. But if we have an empty pipe with a drop of water, it is much easier to think of the drop of water as moving through the air bubble. Mathematically, whether you treat the holes as charge carriers or the electrons as charge carriers in a specific energy band you get the same answer, however it is much easier to deal with a lesser amount of stuff. Hope that clears up the convention for you!

[@NodeEntry]

You guys should really make more of these. I always found animations with simple, straightforward narrative to be the most educational. Great stuff.

[@Melky_Z_dek]

Great Video - Narrated by:stephen hawking wife.

[@burny88th]

is that true??

[@birchual]

haha yeah the voice is bizarre. It is human but as robotic a possible. there is a bit at 4.13 when she say "this is a peculiar behaviour" and it sounds like a robot breaking its programming and forcing human-like emotions. good video though!

[@Melky_Z_dek]

andy b No dude

[@burny88th]

DNA Militar haha! How much of a dick do i feel like haha!

[@alexweston7032]

It sound like the woman from richard dawkins "selfish gene" audio book .. way too close

[@HardwarKid]

Another video on youtube titled "Modern Physics Lecture 30, foundations of the PN junction" is a 90-minute lecture on the mathematics and physics behind this principle, which is excellent for people who appreciate a deeper understanding. That said, after having sat through two "electronics devices" college lectures, and watching hours of videos on youtube, this video is by and far the most comprehensive, yet easy to understand coverage of a somewhat complex topic that I've found. Thank you!!!

[@1murkeybadmayn]

I wish I had found this video ages ago, would have saved time with lecturers attempting to explain in their very technically perplex terms.

[@grapadorasingrapas6055]

sure bro? i can make a magic diodos

[@Niohimself]

Best animation I've seen so far. Esp. liked the brownian motion of the electrons/holes and the nucleus charges in the background. That really helped me connect the pieces.

[@omraikar8517]

How can anyone make such perfect video...it explains all concepts regarding pn junction!!hats off to the makers!!👍👍

[@ritwikgupta7540]

Awesome video....cleared all my doubts....no wondering in how people in Europe are so talented...hats off

[@ronniewilliams3420]

Such lovely graphics, the production values...it takes an area of science that is so vast it continues to rewards mankind...

[@sirronnitram8937]

Sounds like Leonard's mother.

[@OMiki90]

You ruined this video for me now! :D

[@tyson6695]

best explanation so far,cant believe it took my college lecturer 3 hours to explain this

[@tambufra]

This video is really impressive for the quality and for the easy comprehension of the diode functionality

[@fmgomezcampos]

Hi! Yes, holes move. The didactical model indicates that they go from the P region to the N region when the junction is made, so they leave a region "empty of holes". Holes move because they are something like dangling bonds. Since other electrons in other bonds can move to the dangling bond represented by the hole, you can imaging the hole moving in the opposite way.

[@delkinlixo5350]

The best video I have seen so far on this topic. It covers pretty much the whole theory and leaves the maths to the curious ones. Parabéns de Francisco para Francisco.

[@bthrun90]

By far the best visualization of the inner-workings of semiconductors that I've ever seen. Well done and thank you for sharing!

[@elpak]

Great, great video! I am probably going to recommend it to my students. I have one suggestion, maybe could be added as "annotation" to the video. A key part of the explanation probably goes too fast for someone learning this, when the depletion region is first mentioned. It would be desirable to remind the viewer explicitly that when the holes diffuse to one side and the electrons diffuse to the other, they tend to eliminate each other when they meet (since the electron simply fills the space of the hole, as was marvelously explained at the beginning) and this explains why the free carriers disappear in the middle "depletion" region (the animation shows the carriers disappear but it happens too fast to notice if you don't look for it).

[@fmgomezcampos]

Thank you very much for your kind comments. Yes, you are right, there are full lectures elsewhere about the pn junction, and with this video we wanted to communicate with simple ideas the way it works, so the students could catch the basis and better understand the theoretical formalism. We are really happy knowing you consider it is helpful. Thanks!

[@uberscientist]

Don't listen to the haters, this is a wonderful video with great animations and explanation. Also if you want to make one about transistors that would be awesome~ THANK YOU for the job well done!

[@fmgomezcampos]

Minds Forge Hi! Thanks a lot for the support! Nevertheless, sometime the haters do their job suggesting new ideas for future videos (they could be more polite sometimes though) ;-) We have one on transistors and about LEDs, check it out in my channel! I hope you like them. Thanks!

[@supungamlath]

The best video so far on PN junction. Thanks!

[@melekkhalfallah5046]

just woooow !! I can't imagine better than this video to understand all that !

[@foohines]

And suddenly, I finally understand the P-N junction. Thanks a lot for this!

[@chrisraj7776]

this is by far, one of the best explaination video i have ever seen. thank you for the clear explaination and those good animations!

[@jaidevmysterious]

By far the best video I have ever seen! Such simple teachings giving great impacts.

[@florispavlou5599]

Amazing and unbelievable presentation! Great Jod! Thumbs up!

[@matthewcrowley6115]

Very nice video, this covers hours of lecture time in my Electronics class

[@Harshil2456]

Excellent video on PN junction!!! This video clarified the key concepts to me. Thx a lot....

[@nakt0]

This is a excellent explanation I thought it was hard after reading my book all day yesterday but this video made it so simple. Thank god for you guys!

[@jobmoharramy2106]

Love the way you explain, thanks alot for sharing

[@gopalch.mukherjee1960]

Thanks to you tube to keep an such arrangement in the network world for acquiring knowledge in respect of all subjects.

[@rohitsarkar7854]

This is hands down the best explanation that I have come across. The animations were superb and facilitated clear visualization and made understanding the concept a whole lot easier. Keep up the good work :)

[@spiroamo]

Very Nice and Useful Video ever seen till now. Thank You

[@YaskSrivastava]

The Most amazing video on diodes I have ever seen in my LIFE! , Thankyou so much!! :)

[@SyntekkTeam]

Great video I've spent 5 weeks taking a class on this topic and I feel like I learned more from this video than all the school

[@swadeshtaneja3512]

Excellent explanation. I like the voice very much. I do not understand why do people give negative comments unless it is scientifically incorrect.

[@SimranKaur-wc2df]

That was great, so clear and well demonstrated! And that LED man at the end has some moves!

[@Janmejoyslg]

It is THE BEST physics video I have ever watched. You deserve a hundred likes. :-)

[@DavidSiorpaes]

Great video, keep on with the good work!

[@teer21archery8]

very helpful......especially before the eve of an exam....thank you most greatful

[@SailaMaham]

Wonderful explanation! Beautiful animations!! Thank you!

[@VAYS1987]

Thank you, I like the way in which you showed the principles of this process.

[@RohitBhat87]

This is an EXCELLENT video! Wonderfully explained and presented! Thank you so much!

[@m4heshd]

This video is Excellent. Understood A-Z. Thank you so much.

[@AlbertoMartinez-sb1rj]

Awesome video it deserves more views. Me ha encantado el video, muy ilustrativo y una gran ayuda se merece más visitas!

[@johnbabatola23]

This is just too beautifully explained. I can't fully express myself. Great job.

[@fmgomezcampos]

Thanks for commenting! Well, you are right more or less. Holes and electrons tend to diffuse, and the electric field prevent them to diffuse, so that's the equilibrium. With an external voltage you could reduce the drift current (equivalent to reducing the ramp height), so the diffusion current is not completely prevented and the device has a net current due to diffusion.

[@hdagist]

Excellent video I have ever seen on youtube about P-N junction

[@wouterwesselink3096]

Incredibly clear, well structured explanation, very rare to come across. Thank you!

[@uumeran]

This is a great video; the visuals are extremely helpful in the explanation. Thanks!

[@tusharshivan9559]

So special video for student to understand the PN junction precisely. ;)

[@tinkeringlabplus2516]

Great way to learn semiconductor. A very powerful tool for auto learning

[@yourstruly8654]

how could something be so perfect!!

[@AhmedHan]

"The diffusion of electrons and holes creates a region depleted of free charge particles." BUT WHY?? This is the most critical point on understand the PN junction, and it is just skipped!

[@fmgomezcampos]

Hi! well, it happens just because of... the diffusion :-D If you can picture out how smoke moves in a room trying to occupy all the available space, you could imagine that electrons would tend to fill all the available space. It's the same physical process: the diffusion. Thanks for commenting!

[@AhmedHan]

fmgomezcampos The result of diffusion never gives an empty region. For the example of smoke, when smoke diffuses inside a room, no area lefts depleted of smoke. If the free charge particles are randomly spreading around, then why don't they stay away from that depleted region?

[@MisanthropeGR]

AhmedHan intuitively i think that during the production of a PN junction when P and N region meet for the first time, the free electrons of the N-region tend to fill as many holes from the P-region as they can due to their disorderly movement. But they don't have so much kinetic energy to fill distant holes but only the neighboring ones, thus creating a barrier. Applying a proper voltage drop you can make them move through/overcome that barrier. Also the analogy with the smoke diffusion in a room is irrelevant because PN Junction is not a consistent space. Actually diffusion takes place at P and N region seperately but when they are combined..a whole different story.

[@margaritaville32]

Hey Ahmed. The region is created because the free electrons from the n-type fill the holes in the p-type. It comes down to atoms and molecules wanting to fill their outer layer, in this case, with eight electrons. A silicon molecule in the p-type will have 7 electrons in its outer shell. When a free electron happens to come near, it'll join the silicon molecule which'll then have a full shell of eight electrons. Once a molecule has its outer shell filled, its reactivity is low. Thus, any more free electrons coming by will be rejected by our filled silicon molecule and the molecule will hold on tight to all of its eight electrons. Note that this molecule is also now negatively charged since it gained an electron (7 protons, 8 electrons). Eventually enough of the p-type silicon molecules with holes will fill this way, creating a band of negatively charged silicon molecules that will repel any electrons trying to move through it. This is the important "region depleted of free charge particles" since there aren't any holes or free electrons left and any new free electrons that might venture in are being repelled by the negatively charged silicon molecules.

[@alexweston7032]

If im not mistaken all this atomic stuff is theory .. we have not been able to see the atom. Once I saw a picture of a fuzzy cloud that was blue and red , but the resolution was bla... they came up with this theory way before they had the technology to verify it .. so don't hold it as high on a factual chart as we can observe inertia in billard balls. the key point is that all this information is a good model for graphically placing how we observed the results of a large set of variables and their relationship with one another. So ya all those who want to go deeper need to get down and dirty and produce an ACTUAL film of a microscope observing this phenomenon happening. Sometimes I think back to how this happened (departing from vacuum tubes) and how this may be just heat energy.. and not electron diffusion.. but thats merely hypothesis.... One thing that keeps me open minded is that our computers that run the electron microscopes(TEM/SEM) are translated by algorithms into something that is common language to us >> A screen/computer monitor.. In a 3d world how do we see all planes by merely looking at one flat layer/vector ... I think there will be much merit in using an analog type system ,, perhaps even departing from using electricity and circuitry ... It almost makes me say ,, we need to find something lighter than light to observe light ... caz if you observe a cardboard wall with a tractor you may move/break it before you know its there ..... there is much more to life than is taught in books, remembering that helps me get inspiration to setup an experiment to observe something myself and deduce my own unbiased perspective free of precepts. I use these concepts put forth and taught as "ways to remember stuff" , but I keep myself aware and open to the possibility that it is only an observation based on results, this allows for future development and ways to bring forth new utilities/tools/capabilities.. caz there are many perspectives.. many sides .. many .. our scientific duty is to find the ones that cannot be disputed(caz they already have and survived) or just .. work .... for now .. maybe forever .. ja .. Love the video BTW ! I don't think I will forget this again .. I can't count how many times I have referred back to check how this works.. seeing this video is MAD helpful !!!

[@hamzaleb9215]

So professional and complete. Thanks for the great efforts.

[@fmgomezcampos]

Hi Aeon, it's conventional current flow, the one that you would observe using a real experimental set up. Electrons are then moving from the negative to the positive terminal of the batery. The current goes in the opposite direction.

[@sangamesh.s8951]

Thank u very much

[@changyuanlin2233]

Very nice! The descriptions are both precise and concise.

[@jakkuwolfinsomnia8058]

I've watched this about 10 times in about two years. I only now feel like I'm beginning to understand how this works.

[@sreevishal2223]

this the best explanation of pn junction diode!!! thank you soo much!!!!

[@ecapers7231]

Very helpful, and I actually like the voice. It's distinctive which helped me pay closer attention.

[@gracieforster]

Perfectly explained! Excellent video

[@juancastillo9066]

Great Job! Well organized, and excellent choice of visuals !

[@Shankar-gs8om]

one of the finest videos i hav ever seen.gr8 work

[@alexanderhenn2318]

Very nice work! Best video about this I've seen! This is even more clear than in textbooks!

[@14xx07]

Thank you so much!! :D Think you helped me to understand the most out of all the other youtube vids!! :D Thank you! :D Please do continue posting vids! :D

[@NaveenKumarbachu_homepage]

excellent video lecture on PN junction diode. I loved it

[@MohdZaid-cl3cg]

You deserve an oscar for this video !!! Great Work

[@theguyoo1]

That was fantastically clear and thorough.

[@Haripriya-fn7fg]

Excellent!Thanks a lot guys,great job

[@princeosei6163]

It is such a great video. Well done with the explanation and presentation of the video.

[@bhanuprakash3274]

supper..........I.......am......happy .......for .....this.....I.enjoy a lot by seeing..this video

[@lancelovecraft5913]

Cool video the soundtrack was great and it made sense of the text that i am reading. also i liked the skateborder doing the frontside flip.

[@IvanSchoeman]

I wish all educators understood that more information creates a complete understanding that is easy to remember.

[@Syraxius]

I'm amazed by the effort put into this video. Really clear and concise. Thank you!

[@ShahriarZayyani]

great video. well done, concise and precise. great for a high school level introduction.

[@eunicesantiago8223]

Amazing Work!!!! So detailed, now I understand what my professor was trying to explain. Muchas Gracias por hacer el video, sigue haciendo mas.

[@rawfreshoner]

very well explained and amazing video production.

[@ravalparth7312]

A VERY GOOD CONCEPT CLEARING VIDEO OF PN JUNCTION .

[@sharanyachandapatla2990]

Very useful video for students with superb graphics

[@edwcaran]

Excellent video; thanks for sharing this educational help. I used it in my classes.

[@gdelospalotes]

Best representation I've seen, thank you!

[@arromaljjayan8996]

really gud video.....helps us get a clear view on the PN junction

[@m.amulya2158]

Excellent Video. Hats off. please post more videos on Theory of pn junction in detail.

[@nanimunna1825]

superbbb. really helped me. expecting still many such videos too...!

[@ajairainception]

yep!! this is the most helpful video i could find so far!! thanks guys!! this helped a loooooot!! can't be thankful enough for this awesome presentation!! :D:D

[@TheVegesquid]

Incredibly helpful. Wonderful analogies too. This really cleared up some confusions of mine on the topic.

[@ankityadav2606]

Thumbs Up to the animations and sound effects!

[@ankitsingh7447]

the best i could find on net.... thanks

[@schmidtzcargolbull]

TREMENDOUS video. Thanks.

[@dummmylog3070]

Thanks for making this clearer

[@camilovinatea7747]

This is just marvelous, thanks a lot!

[@schmidtzcargolbull]

One of the great animations, well done