Arduino Tutorial 2: Understanding How Light Emitting Diodes (LEDs) Work

[@ajyu7289]

came for an arduino tutorial, stayed for the physics lesson

[@brianm.3611]

Me too

[@kevinjimoh2921]

Literally, wasn't expecting this dude's knowledge to be this ridiculously high

[@djbroake9810]

Yeah, just amazing.

[@saubhagyadhungana7025]

Bro i solved my doubts of semiconductor here

[@basil9633]

Ikr

[@bazar9000]

1:52 How light bulb is working 5:18 Conductor and Insulator 6:00 Semiconductor (tailored martial) 7:00 Silicon wafer 8:00 How semi-conductors (i.e. Crystalline martial) actually work 9:30 Discrete energy levels => Energy allowed bands 10:20 Conduction (Valence and Conduction bands) 12:50 Intrinsic (heating) semi-conductor (-ve and +ve charges conduction) 17:05 N-Type, induction via -ve charges in the Conduction Band 19:43 P-Type, induction via +ve charges in the Valence Band 21:56 Quick summary of semi-conductors covered 22:25 How those semi-conductors types lead to LED? 23:45 Offset bands when N-P are combined 24:50 Applying +ve voltage to N-P (lowering barrier causing light to emit) 26:30 -ve charge over +ve charge (Electron, Hole Pair Recombination => Photon) 27:47 How the light emitted from an LED? 28:40 Applying -ve voltage to N-P (increasing energy barrier preventing light from emitting) 29:40 Quick Summary 30:16 How to correctly hook-up a diode (+ => P-Type, - => N-Type) 31:20 Diode response graph (I vs. V) 32:35 Why resistor is needed when connecting LED 34:30 How the color of LED is generated 37:07 TL, DR version of the lecture Thank you sir for your knowledge share 🙏

[@isaiahwhitney8168]

thank you for your breakdown

[@nitinchauhan530]

Not all heroes wear capes! (Assuming you don't. If you do, then some heroes do wear capes).

[@Seerat.Bashir]

@@nitinchauhan530 haha🤗❤

[@sethsgamingclub2061]

@@nitinchauhan530 lol

[@sionadias2931]

true @Nitin Chauhan these are the little things that help and restore faith in humanity

[@arch2044]

Finally my search for the perfect teacher is complete.

[@smokyb3264]

This guy is amazing , his understanding and ability to convey the information to people with less knowledge on the topic is remarkable.

[@darrendobbs1185]

Was thinking the same thing.... Where was this guy when I was at school. Epic teacher

[@nikkip3385]

My physics teacher at school should have been lecturing at university. Sadly he wasn't so great at giving 13 Yr olds info in an easily digestible way. I'm finally starting to understand the basics a bit better. 40 years too late but better late than never. 😂

[@Thatbushpilot]

Agreed! He’s amazing. Such clear and thought out explanation.

[@rajdahiwade]

Sir You Are Genius...

[@pauln1557]

I'm a 62 year old mechanical engineer, I was inspired to buy an Arduino by a 10 year old, it's never too late to learn new tricks!! I'm working through your excellent videos; Now, thanks to you I understand why I have to put that 200 ohm resistor in series with the LED. Regards Paul in NZ.

[@paulmcwhorter]

Go for it!

[@anishgurjar6138]

Thanks a lot, Paul. I learned Arduino, Raspberry Pi, and 3D printing from you and made a lot of cool projects. 2 of them reached national level competitions. I am really grateful I found you.

[@chychy9515]

How much time you had to put to learn Arduino?

[@mattjohnson320]

wow ive never heard of you

[@RohitSharma-uw9ec]

@@mattjohnson320 he said national not international 🤷🏻‍♂️

[@isseii4137]

@@RohitSharma-uw9ec Plus to be recognized by media he would probably have to win those competitions, and as getting to let's say 100th place can be great personal achievement it doesn't bring much attention to your person ;)

[@davidlee9924]

this is the best teacher i’ve ever had even though he is not my teacher

[@Zalmoxis-fj6we]

It is very sad how in some faculties there are teachers only for salary and put courses at which only some people assume that they understood or did not understand at all, and apparently you have explained hours lost in my college only in about 40 minutes. Thank you! You made me understand how a diode works. What good would it be if we had people like you who would explain it so well.

[@thatguy-oo2pz]

I seriously did not expect this video to turn into a full-blown physics lesson! But thanks so much! I've never met any other teacher who would go into so much detail and make it so interesting!

[@poppycock-w6y]

In my opinion there is nothing more valuable than a good teacher.

[@1943crab]

I am 80 years old. I studied electronics when I was in my 20s and have worked with radio and computers since then after I got my ham radio license, sometimes as a hobby, sometimes as a vocation. I have known and understood this material all that time but I never put it together what frequency of light the LED would emit. Thank you for stimulating an old brain to keep on learning.

[@script_kitty]

Dang. You can tell this man really knows his stuff. He is able to explain it in such a way that a child would be able to understand it.

[@povnw8985]

Einstein said, "If you can't explain it to a child you don't understand it.".

[@theotherlemon966]

I am a child and I approve this message

[@sharmisthadas7896]

Yes. It is very true. SAME!

[@naamyagulati5469]

I'm 10 and I totally agree!

[@ChrisPackham1]

I came here to learn Arduino but I've already learnt so much more, well done, I really wish I'd had you as one of my teachers when I was younger.

[@jameshalpin1274]

I’m happy I have him while I’m young

[@doaedoae1210]

@@jameshalpin1274 me too

[@rkosingh4514]

@@doaedoae1210 take that knowledge and run with it . you'll go far and high .

[@impulseimp1035]

Never too late to learn something new

[@cartbook]

Literally learned a 10+ hr physics lesson in just 38 mins...much simpler and easier to understand. Thank you.

[@olegvelichko1659]

This is fantastic. I’m gettin a warm and fuzzy vibe off of watching these videos. Why am I thinking “Bob Ross” right now?..

[@OverlandOne]

Exactly! Paul is the Bob Ross of electronics.

[@CavalierFeynmanFan]

I am a physics instructor; your lesson is a brilliantly articulated explanation accessible to anyone who is interested in learning. Thank you for this contribution to physics teaching excellence.

[@419kings5]

Im only 14, and Im loving your series!

[@ROY-mh7qy]

same!

[@chiararoberi6855]

same!

[@superprocz]

Im 11😃

[@user-fw5gr6gn3z]

@@superprocz Im 13

[@taylorjarvis4602]

Im 15 but samw

[@caltech-wirewizard]

Hello Paul, I really love your Arduino tutorials, I've been watching all the lessons, and have given you a "Thumbs-up" on every single tutorial. I love your teaching style. I/myself, am a retired Engineer with a Masters in "Electronics Engineering and Computational Mathematics" from CalTech. Back in my engineering days, Ardunio never existed. I wanted to keep busy & stay active in the field, and this video series has been excellent. I completely understand why you want your followers to understand the physics and the math behind some of your homework assignments and I agree with it whole heartedly. However, in this case, at 33:50 you point out you need a Current Limiting Resistor and why. But, you didn't say HOW you arrived at 330 Ohms. Choosing the correct resistor value is imperative to insure your LED receives proper voltage and current. To ensure you have the correct resistor you will need to know three values from your circuit. Vs - Supply Voltage - This is the power supply that you are using to power your circuit. Vf - Forward voltage for your LED. This is the voltage required to turn on your LED. If - Forward Current for your LED. This is the current required by your LED for operation. The Forward Voltage & Forward Current can always be gotten off the LED's datasheet. (Which we don't have) With these numbers you can calculate the resistance required with the following equation. R = (Vs - Vf) / If Example: The Arduino's Supply Voltage is 5v. The LED's Forward Voltage (according to it's Datasheet) is 2.4v. (ASSUMPTION for this example) The LED's Forward Current (according to it's Datasheet) is 15mA (ASSUMPTION for this example) This means we need to "drop" 2.6v (Vs - Vf). Using Ohm's Law: E / I = R 2.6/.015 = 173.33 Ohms Unfortunately, we don't know what the The LED's Forward Voltage or the LED's Forward Current is. I'm just including this as a real life requirement when designing circuits.

[@PPlankBeam]

40-odd years ago at school we did valence in chemistry and I just didn't get it, but I learned enough to pass and get my chemistry o-level (UK). Today I get it. Thank you, you're an excellent teacher.

[@furrepanther]

Paul, thank you for condensing what are multiple complex physics topics into something comprehensible to a typical person. Your series is excellent. As @AJ Yu said 2 years ago, "came for an arduino tutorial, stayed for the physics lesson." I've always said, "learn the fundamentals FIRST; knowing WHY things work the way they do helps you figure out HOW to use them; when you get to more complex topics the fundamentals will see you through."

[@jacobzacharewicz5661]

When I first saw the beginning of the first lesson, I thought you were going to be boring and I really wasn't going to learn much, but by the end I was able to write basic codes and I wasn't bored watching it! You have a real talent for teaching about science and coding!

[@kerryduan5816]

same

[@benjaminbaron3209]

Electron-Hole-Bear-Recombination is by far my favorite phenomenon in physics!

[@povnw8985]

The Electron-Hole-Bear and the Maiden fair!

[@onlyonce3232]

I started a job with the title mechanic and it became painfully obvious that my job was chemistry, Inc, electrician and operator. All things I know nothing about. So I bought an elegoo kit to get a better understanding of electrical components/sensors and stumbled on your videos. I really appreciate you and all that you do. I know that this video is older and you may not check comments but I just wanted to say thank you

[@wings907]

i' m a new high school teacher introducing computer science and electronics. This lesson is so inspiring!!!!! Thank you for making great video.

[@roldanmarco1856]

I'm here to learn arduino but wow, that's a good review of my electronics. Keep up 👏

[@grafophone]

Great video Paul. I'm 73 now. I studied electronics in the late 60's and early 70's, when vaccum tubes were king. I've learned about semi conductors, diodes, transistor (of all kinds), IC circuit, linears, buffers, counters and so on......but not microprocessors. I have work in electronics as wiring, soldering, and also drafting printed circuits. Arduino is for me the unknown. I purchased this week from Amazon the Elegoo Mega 2560 Project The Most Complete Ultimate Starter Kit. With your help and some of my efforts I will soon be able to work and and learn about semicontrollers like Arduino. Thank you so much for these state of the art videos, you have an exeptional talent in popularizing things so people can have a good idea concerning highly complex materials. BTW, watching No.2 tutorial concerning how LED work was a good refresh.....since I quit electronics business 30 years ago. Sincerely.

[@danielsaenz5570]

So much happens in such a simple component! Really enjoyed how you showed the physics behind it, rather than saying "An LED will light up when you pass current through it" You actually teach why it works! Thanks a lot Paul!

[@smartypants5036]

I have done a lot of stuff. Built power supplies, made filters, played with ham radio and still not under stood at a fundamental level what has just been explained. I am hooked on these tutorials already. BRING ON THE NEXT ONE. I learn how this guy teaches.

[@munnaseeksjustice]

I wish I had access to these videos on KZbin when I was growing up.... Amazing clarity

[@boneitch]

Years of bad text books and a teacher that told me I was stupid for asking questions had me convinced physics just wasn't for me. This man has shattered this conviction in 20 minutes. Thank you Paul!

[@paulmcwhorter]

Sometimes, those who really know physics are out in the world doing physics. Maybe your teacher was a guy who did not really know if. If he really knew it, and if he loved it, and if he loved students, he could have made a difference.

[@MJCPeters]

My first electronics course was in the mid 70's (tubes). I think we spent over 1/2 the semester on this same concept. I left that class totally confused. NOW I get it!!. thank you. Letting the smoke out - priceless....

[@highfoxninja2582]

For the first time in my life, I'm actually having fun from a lecture. Thank you for helping me get started on a new journey with the Arduino, and also with programming

[@Ericx2010]

Your tutorials are just remarkable. Keep up the good work! Greetings from Germany/the Netherlands.

[@paulmcwhorter]

I have visited the Netherlands twice . . . beautiful country! Loved the chocolates there.

[@the_oao_raider]

2 years later and still helping people, thank you so much!

[@paulmcwhorter]

Glad I could help!

[@tellder1]

Man I wish you were my physics teacher in the school. These tutorials are absolutely amazing! We not only get to learn about Arduinos and their programming, but also what's more importantly, the fundamental understanding how it all works under the hood. Thank you Paul!

[@georgiosgiakoustidis6617]

Your tutorials are amazing, thanks! Towards the end of the video, where you explain the relationship between the energy and the frequency, I would like to point out that f ~ 1/λ would be correct or f = c/λ of course, with c being the speed of light. This comment is mainly intended for the people that also learn some physics throughout your tutorials :)

[@chetk4624]

I started in electronics back in the late 60's in the Air Force. Wound up retiring from the Semiconductor Manufacturing industry, Photo lithography. Thanks for refreshing what I forgot over the years. Got the Auduino kit and am amazed at what it contained.

[@khalidiqbal4769]

Never got such easy, understandable, and comprehensive lectures in my life. Dear Paul, you are a magnificent person with unparalleled skills for teaching. Teacher of the teachers. God bless you.

[@Whole_Note]

This felt like being back in a classroom. That's exactly what I've been looking for in an Arduino series.

[@supernova5107]

Excellent tutorial. Best description of a n type and P type I've heard.

[@TBoy205]

too bad my engineering professors at UT Austin don’t know how to communicate as well as you do...can I come take your high school classes? lol

[@sahanag836]

Come to A&M bro

[@jonathanself1263]

I switched majors from aerospace to arts because of the useless physics/engineering profs at UT Austin.

[@bobwilson8838]

Smart People are hired in Universities for many reasons. But I do agree that many of my engineering professors did not have teaching gifts or skills. I believe that many wanted to pursue other goals like research on their pet projects for example. I learned you had to research first who is teaching your subject before signing up for a class.

[@ancala4140]

pretty much agree, not about to point certain institution/group but about learning and teaching, as i recently realize that to teach not just limited to understood the things but also able communicate it

[@lg2058]

First electronics fundamentals video I watched in full.

[@sondrehyland3818]

"You can never get the smoke back in" had me dying; love these small jokes

[@sahityaposani4757]

he didn't need to do all this work, but has done it so excellently for us. LEGEND

[@VivekYadav-ds8oz]

You explained Semiconductors better than my physics teacher could. You're multi-talented. I've huge respect for you 😎

[@qz9720]

Honestly one of the coolest videos I've ever watched, didn't expect such an in depth and easy to understand explanation on semiconductors and LED's, my mind is blown.

[@dougrowell7817]

Again, I've seen this stuff before ( I have a degree in Chemistry 30 years back) , but so good to have it reinforced is such a friendly way.

[@ALIENMACHINES]

You explain things really well and at a speed that makes it easier to understand, less fast jabber and more measured understanding. I am really enjoying this series, thank you

[@foongsteven]

How I wish I learned in this way in high school! I'd be a scientist today...

[@newguy3588]

Never too late m8

[@nileshshah7516]

Excellent explanation of semiconductor material and diode causing light emission. I am a medic by profession but slowly getting into this new passion. Thank you Paul. You are great!

[@temukaify]

I really need that *Love* emotion here. This has been the most scientific, interesting and educational tutorials I've come across here.

[@farmerdave7965]

Atom one "I lost an electron." Atom two "Are you positive ?"

[@amroghachim3006]

😂😂😂😂😂

[@kenmeyer100]

Its back now, so I guess that was a false Positive

[@povnw8985]

I laughed at this even though I shouldn't have. fml.

[@grahamovermyer5987]

I started messing with arduinos in college as just a fun activity separate from my degree. The course I was going through paid little attention to explaining the underlying physics of the parts of the circuit, and focused more on specifically programming and circuit design. I love both approaches, but as someone who has burnt up many led's when trying to learn the basics, I appreciate your thorough explanation and am on board for the rest of your course!

[@danwolfe7665]

Holy cow, I understood more in this 40 minute video than I did my entire second semester of electrical engineering!

[@ComedyPodcastClip]

"Bob Rose's video on the inner workings of semiconductors left me absolutely mesmerized! He had me at the edge of my seat with excitement, breaking down every component with such enthusiasm and clarity. I never knew understanding how transistors work could be this entertaining. Thank you, Bob, for delivering a truly electrifying educational experience!"

[@pauldunning1756]

Found my new binge watching series

[@Basketball891]

what is it?

[@charleshicks5253]

I’ve been in electronics since high school (1970’s) and years of electronics in the Army. I have never had anyone explain anything the way you explained the LED. I understand it much better after this video. Thank you so much.

[@jankyyard5610]

Thank you, sir! This is the perfection combination of theory and application of arduino tutorial that I encounter. I learned a lot from you.

[@patrickgonzales8072]

These videos are gold!! I came here to learn how to use my Arduino. I bought it years ago and played around with it for a few months and then it sat on the shelf. I am glad I found your channel. Not only do you explain the fundamentals, but the theory is what has really peaked my interest. Keep up the good work!!

[@paulmcwhorter]

Great to hear!

[@didifady1641]

Man, your awsome. My dad has been trying to teach me these things and i just didn't get it. I thought technology just wasn't my thing, but I was wrong. I love your tutorials. Thanks man.

[@didifady1641]

I'm only 11 and I'm already learning so much!!!

[@aaronmilliman7685]

Yesterday I used one of my kids Arduino. Today my kit came in and am excited to play with Diodes tomorrow. My goal is 1 video a day! Thank you for all this information. It will educate me so I can change careers.

[@versatilegeniuses9374]

This is the best thing ever for me !!!

[@thirupathaiah2981]

I think u got the experience over the years... How a student can show interest of their subjects.. Respect..

[@DavidStockford]

Brilliant explanation. I was able to follow you fully. Thank you

[@paulmcwhorter]

Well I had trouble learning this stuff, so I try and go slow when teaching. I know how hard it is to follow some fast talking teanager.

[@speedbag67]

At first i thought... 'Where is he going with all this'? But by the end it all made perfect sense... I sat here while my Arduino blinked at me for 38 minutes. All I really wanted was to do something more with my Arduino... I ended up with a MUCH greater understanding of what my Arduino was actually DOING for those 38 minutes...... BRAVO, Sir! You have put an electron of knowledge where I didnt even realize there was a hole... =)

[@jonjon3829]

Are you sure this is part 2? This went real, fast.

[@jobistore7757]

This is an exceptionally good explanation about the basic Physics behind LEDs, without going through all the Materials Science, Mathematics, and Advanced Physics that are applied in the development of such devices. This is a good start for kids who may want to become Semiconductor Physicists.

[@lamp007]

You explained what I "learned" back in college. You made it make so much more sense and I could actually understand it.

[@danielroh4543]

Paul you're an amazing teacher! Easily digestable, with plenty of visual aid, and super comprehensive. Seriously, I never expected to learn this much about semiconductors in a mere 40 minutes! Thank you!!!! Also, after the video stared directly at my "color-changing" LED lamp. Partially blind now but can confirm its made of seperate materials lol

[@paulmcwhorter]

Wow, thanks!

[@leftymichael3465]

This guy is good! I mean if it didn't make sense before just keep watching it over and over and you WILL understand it after a while! Thanks Mr McWhoter

[@deity2507]

Sir, you are my huckleberry, if every teacher in the education system were like you, the progress in humanity would be phenomenal. Definitely hooking a brother up!

[@FumblingButtons]

You remind me of one of my all time favorite teachers. I never was much to listen in class... but some teachers just require your attention and speak in a way that is interesting.

[@alishevas]

Wow, this was such a great lesson! I do not think I have ever understood how semiconductors work when we discussed it on physics lesson but now I am pretty confident. It is crazy how it is well and interestingly explained. I also understood how LED works! Thank you so much!

[@michaelap7237]

You're so captivating, I have a concentration problem but I get lost listening to your every word. I'm amazed. I honestly can't believe teachers like this exist.

[@Ghoul-sb5yh]

It's incredible how you explained semi-conductors far better ,on a video relating to Arduinos, than my actual Solid State Chemistry teacher. Awesome video and explanation.

[@itzikifergan417]

So bright explanations, I'm an Electrical and Electronic Engineer and you gave here correct and accurate things. thank you. subscribed!

[@mikeflor7446]

I've been around electronics for 40 years, (now retired). What an excellent tutorial Paul. My grandson is coming up to be interested in electronics. I sure as hell will direct him to this website when he is ready. Thanks for making my life a little bit easier.

[@paulmcwhorter]

Fantastic!

[@andrecoulter8126]

I started at lesson 27 then came to lesson 1 and 2. This is a lot of information for an entry level tutorial, but much needed.

[@mikerilling2745]

Just ordered my kit at 10 o’clock at night. Amazon will have it here before 8 o’clock in the morning.

[@arula1002]

To be honest Paul, I have been blindly following the terms electrons and holes, by the theoretical teachings that I learnt in the past from my other mentors, they failed to reach out to blind heads like mine. But your teaching method of looking under the hood, explains with an elaborated way with easy to understand examples, now I learnt how in reality the conduction happens. Thank you so much for explaining that in details and clearing up with the strong fundamentals for a good foundation in electronics with semiconductors, now with that learnt information, next tutorial I can follow up very well. You are a great teacher Paul!

[@thomasunderwood1983]

i never learned electron hole theory in my electrical engineering class from the 1980s. Teacher did not speak understandable english. Glad I finally got it. Not saying someone who spoke english could have taught it either. It is a very tough subject to master just from reading a book. I never got it from reading the book either. Thanks, finally I got it.

[@MrMattMagoo]

Not gonna lie, I definitely rewound a few times to re-listen, but I feel like I got it. I was a lil leery of the direction at first, but I'm so glad I stuck it out and kept watching. I feel like what I just learned, will be invaluable in years to come. Thanks for your time and effort on this.

[@paulmcwhorter]

Well done!

[@luciferfps-fury5814]

Wow! I study industrial engineering and I think you just explained a whole section of material science in the most intuitive and simple way I've ever heard. That was brilliant.

[@paulmcwhorter]

Great to hear!

[@ErlankBru]

When I start making my own analogies (it's a byproduct of my adhd in a way), it's a good sign for the lecturer that he made his lecture very understandable. :D

[@reaper060670]

HEY PAUL my friend.. I wrote my 1st ever program this morning at 03:30ish.. heehee1 I'm very grateful to u man.. I began working for a company that designs boards for their own Routers so this is all new to me but I'm delighted to havbe found ur channe and all these tutorials. I'm learning so much right now Paul.. Thank you so much. I love learning and I'm supposed to be going on some courses paid for by the company in the new year. These tutorials are going to give me so much information to carry forward. Learning about Electrons, Valence Bands, etc and Diodes and resistors is awesome.. I'm looking forward to part 3.. Take care my bro..

[@paulmcwhorter]

Welcome to the FEW, the PROUD, the CODERS!

[@426F6F]

I wish I knew what technique you used to explain this because this lesson was very easy to understand and remember! You are a phenomenal teacher, thankyou for all you do, Paul!

[@marekmoravcik3508]

Mr McWhorter, it is poetry to listen to a great teacher. Small repeated steps lead to greater results, like the electrons each moving from one bond to another together resulting in a spark of bright light. But it never goes without a strong will and dedication (fixed resistor) to bring balance to rapid change. Thanks for inspiring me and wish you all the best!

[@supernovic99]

This was an amazing video! I always hate it when people just tell me that this does this so do this. Now, I actually understood how an led works and its a lot more intuitive to do things. Thank you so much!

[@gerardomondragon7191]

Thank you Paul for giving my 10 year old son and I the best semi-conductor class we could’ve ever imagine. Best part...my kid is so happy and motivated to continue learning from you, and so am I. Once again, thank you!

[@paulmcwhorter]

Fantastic!

[@magedhafez5176]

extremely grateful for reviewing my electronics course I took 30 years back. for some reason I feel like reviewing calculus and DE as well but thats over ambition I think :)

[@neilfurby555]

Quite superb...at least for me. content, visual, delivery just right. A gifted communicator, one of the few that delivers great content without resorting to extremes of personality and show business trickery. Excellent...look forward to working through all the lessons. THANKYOU

[@heismysavior21]

I can't wait to learn more! 20 year elevator technician/troubleshooter here looking to understand coding better! I got down to 13ms on/off before I couldn't distinguish the blinking any further. Great video, great teacher!

[@iuniamuntean5796]

This video literally made light in my head. I had previously learned this stuff in school, but it was taught in such a theoretical way that it didn't feel connected to the real world. Synapses were fired, connections were made and gaps were bridged tonight. Thank you for this awesome video!

[@slnuygn]

Amazing explanation and video. Made me realize that learning for yourself and by yourself is way more fun and efficient than the subject being imposed to you in school. I hope you are doing well sir!

[@chrishamby227]

I just finished my industrial electrical maintenance technician degree and this is by far the best explanation of a N type and P type material. Thank you.

[@paulmcwhorter]

Great to hear!

[@aslayadanadanidris3782]

2 years and the content is soo helpful i love it

[@rachaelb9164]

Interesting way of teaching this. I’ve only ever seen it explained showing the little atom diagrams with the different layers of electrons (inner shell vs outer shell, etc). I am an X-ray tech and understand the basic physics of how photons are created but this shows why led’s don’t work when hooked up backwards.

[@vivekgudise3379]

He was showing the potential difference or voltage as an analogy to gravity to make us understand better.... That's effort to be appreciated

[@gabrielgomez1681]

These videos are not tutorials, they are academic seminars. Thanks a lot!

[@curtismarean6963]

I don't say this often, but your a great teacher. Recently I was working with a diode on a model project, now I understand why it was wired up the way it was. I've learned something today. (p.s. - I'm past the half-century mark now. Your never too old...)

[@abhigyanganguly1988]

I'm in my first year of college, and I've had both physics and chemistry as a subject for three years now. while teaching semiconductors, they always started with Energy bands, but never told us why they exist. I remember asking the question and getting the answer "It's out of syllabus" and "Just focus on the syllabus". Finally I got the answer here

[@thegoldenwolf274]

Had to watch this a few times, but I finally got it down. 3 Pages of notes and I feel like I have grasped the concept of Semiconductors and LED's. Thank you for the video professor.

[@paulmcwhorter]

Excellent!