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.
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?"
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.
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.
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.
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!!!
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.
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!
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.
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.
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!
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 :)
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).
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.
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!
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!
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!
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!
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
Hi! To all of you requesting the subtitles, I have included them now in the video. I hope you could get all the details. If you speak Spanish (or other closer languages such as Portuguese or Italian) maybe you prefer to watch the Spanish version. Look for it in my channel or search "Unión PN". Thanks for the suggestion!
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.
+thescottguy Wow, thanks a lot!
+fmgomezcampos it's true
+thescottguy Although I do find the voice somewhat annoying (no offense) :/
By far the best PN junction explanation i've never seen....
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.
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?"
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.
Wonderful video! It explains much better than could I who have been working as an electrical engineer for 3 decades.
Oh thanks a lot! I spent the last three hours trying to understand this, now I did in ten minutes
Great video. You summed up 2 weeks worth of lectures in 10 minutes. Thanks
You guys should really make more of these. I always found animations with simple, straightforward narrative to be the most educational.
Great stuff.
Such lovely graphics, the production values...it takes an area of science that is so vast it continues to rewards mankind...
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.
This video is really impressive for the quality and for the easy comprehension of the diode functionality
How can anyone make such perfect video...it explains all concepts regarding pn junction!!hats off to the makers!!👍👍
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.
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!!!
Thank you for your lovely comment! :-D There is also available a Spanish version of this video :-D
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.
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!
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.
God Bless, whoever created this. You saved this engineering student's butt. :D
By far the best visualization of the inner-workings of semiconductors that I've ever seen. Well done and thank you for sharing!
Thank you very much! I appreciate your comments.
Awesome video....cleared all my doubts....no wondering in how people in Europe are so talented...hats off
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.
jjjcuxzuf
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!
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 :)
I wish I had found this video ages ago, would have saved time with lecturers attempting to explain in their very technically perplex terms.
sure bro? i can make a magic diodos
best explanation so far,cant believe it took my college lecturer 3 hours to explain this
this is by far, one of the best explaination video i have ever seen. thank you for the clear explaination and those good animations!
By far the best video I have ever seen! Such simple teachings giving great impacts.
1000% clear than my lecture
Tyy
That was great, so clear and well demonstrated! And that LED man at the end has some moves!
Thanks to you tube to keep an such arrangement in the network world for acquiring knowledge in respect of all subjects.
Thank you, I like the way in which you showed the principles of this process.
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).
just woooow !!
I can't imagine better than this video to understand all that !
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.
The best video so far on PN junction. Thanks!
Incredibly clear, well structured explanation, very rare to come across. Thank you!
Excellent video on PN junction!!! This video clarified the key concepts to me. Thx a lot....
Amazing and unbelievable presentation! Great Jod! Thumbs up!
This is just too beautifully explained. I can't fully express myself. Great job.
Very Nice and Useful Video ever seen till now. Thank You
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!
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!
Love the way you explain, thanks alot for sharing
This is an EXCELLENT video! Wonderfully explained and presented! Thank you so much!
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
Very helpful, and I actually like the voice. It's distinctive which helped me pay closer attention.
Very nice video, this covers hours of lecture time in my Electronics class
The Most amazing video on diodes I have ever seen in my LIFE! , Thankyou so much!! :)
Wonderful explanation! Beautiful animations!!
Thank you!
Very nice work! Best video about this I've seen! This is even more clear than in textbooks!
So professional and complete. Thanks for the great efforts.
Very nice! The descriptions are both precise and concise.
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!
And suddenly, I finally understand the P-N junction. Thanks a lot for this!
Wooow thanks for your kind comment and support :-D
Great Video - Narrated by:stephen hawking wife.
is that true??
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!
andy b No dude
DNA Militar haha! How much of a dick do i feel like haha!
It sound like the woman from richard dawkins "selfish gene" audio book .. way too close
Excellent video I have ever seen on youtube about P-N junction
This is a great video; the visuals are extremely helpful in the explanation. Thanks!
I'm amazed by the effort put into this video. Really clear and concise. Thank you!
Excellent explanation. I like the voice very much. I do not understand why do people give negative comments unless it is scientifically incorrect.
Incredibly helpful. Wonderful analogies too. This really cleared up some confusions of mine on the topic.
very helpful......especially before the eve of an exam....thank you most greatful
It is such a great video. Well done with the explanation and presentation of the video.
Great Job! Well organized, and excellent choice of visuals !
It's in the credits. It's a song from Nastya Yasnaya called "Otpusti" released under Creative Commons license.
very well explained and amazing video production.
excellent video lecture on PN junction diode.
I loved it
Amazing Work!!!! So detailed, now I understand what my professor was trying to explain. Muchas Gracias por hacer el video, sigue haciendo mas.
Great video, keep on with the good work!
Awesome video it deserves more views.
Me ha encantado el video, muy ilustrativo y una gran ayuda se merece más visitas!
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.
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
I wish all educators understood that more information creates a complete understanding that is easy to remember.
Excellent video; thanks for sharing this educational help. I used it in my classes.
Perfectly explained! Excellent video
You deserve an oscar for this video !!! Great Work
That was fantastically clear and thorough.
It is THE BEST physics video I have ever watched. You deserve a hundred likes. :-)
Good video
Explains the basic concepts quite well
Always useful for a foundation learner
Excellent!Thanks a lot guys,great job
Great way to learn semiconductor. A very powerful tool for auto learning
I'm speechless. Incredible.
This video is Excellent. Understood A-Z. Thank you so much.
great video. well done, concise and precise. great for a high school level introduction.
one of the finest videos i hav ever seen.gr8 work
So special video for student to understand the PN junction precisely. ;)
really gud video.....helps us get a clear view on the PN junction
superbbb. really helped me. expecting still many such videos too...!
Very nice explanation with nice animation.
Thank you very much..........
this the best explanation of pn junction diode!!!
thank you soo much!!!!
This is so easy to understand, very educative, thank you!
A VERY GOOD CONCEPT CLEARING VIDEO OF PN JUNCTION .
Excellent presentation!
how could something be so perfect!!
thank you very much ma'am. the video was really helpful for me....plz keep making videos like this....
Hi!
To all of you requesting the subtitles, I have included them now in the video. I hope you could get all the details.
If you speak Spanish (or other closer languages such as Portuguese or Italian) maybe you prefer to watch the Spanish version. Look for it in my channel or search "Unión PN".
Thanks for the suggestion!
Thank you for the presentation.
This is just marvelous, thanks a lot!
One of the great animations, well done
supper..........I.......am......happy .......for .....this.....I.enjoy a lot by seeing..this video
You are heroes! Tks very much!