Starter Guide to BJT Transistors (ElectroBOOM101 - 011)

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By: Mehdi Sadaghdar

[@ElectroBOOM]

And while we are at it, GO IRANIAN PEOPLE GO! Best of luck in your efforts to take your rights and your lives back! #MahsaAmini

[@mehdikho]

مهتی کارت درسته

[@birgenair301]

Yes

[@enterprisesoftwarearchitect]

King of pop ha ha ha! I love transistors Electroboom!

[@mickeyfilmer5551]

Absolutely. Those women are so Brave. This is the 21st Century- not the 5th. Good for them.

[@PetraKann]

Rights?

[@SultanGamer124_GD]

I subscribed to electroBoom to see him blow things up but now I’m actually learning something from him.

[@playingweirdo4720]

Ikr!! I felt the same.. tbh I'm binge watching Electroboom videos nowadays

[@Jamie-st6of]

you've been learning the whole time! the explosions are a disguise for knowledge

[@dogs-and-destruction-channel]

The explosions are all part of the learning process, it teaches you what NOT to do or how to make fireworks with electricity lol😆.

[@EvanShechter]

That needs to be on a shirt

[@rumpleforeskin1812]

I know I’m starting to panic a little I’m becoming smart

[@rpfour4]

This is a better lesson than I got back in my EE class in the 90s. I learned more in 10 min with Mehdi than an entire semester of hearing about the "glory days" of the professor I had.

[@BariumCobaltNitrog3n]

Yes he's very good at explaining things to slow learners so they walk away feeling like they learned something. But tomorrow...

[@thewhitedragon4184]

Honestly I don't see it. He cut out a lot of information in the video to make it shorter but at the same time he kinda explained transistors as a switch but jump to making amps which drive transistors differently

[@lwo7736]

I bet, your teacher once told you a 20 minute story about his life to try and relate to the class, and you spent the rest of this "entire semester" messing around, ignoring the teacher and just generally being a useless learner. So to save yourself the feeling of regret, you've concocted this "glory days" story to make yourself feel better. It's the same with all of these "I wish my teacher in school was like this guy" comments on every single science influencer video out there.

[@rpfour4]

@@lwo7736 Messing around? This isn't high school. Who the hell wastes money at a university?

[@tunkunrunk]

you learned in less than 10 min because of your EE class back in the 90's . if you were a beginner you wouldn't had understood that fast with Medhi

[@agalah408]

I'm not sure Mehdi should be teaching transistor theory. I think he's biased.

[@hyphen1210]

underrated

[@agalah408]

@@hyphen1210 Yay, thank you :)

[@bluekindasustho3370]

I expected many thousands likes. Many People properly didn't get the joke Underated AF

[@Arjuna_insync]

@@hyphen1210 lol 😜

[@avijatsinharoy8944]

I think he's just a beta male

[@AmoghA]

Whenever Mehdi mentions a capacitor, I know there is going to be an explosion.

[@that1electrician]

That's what we're all here for isn't it?

[@jurijavsenak]

😝

[@flaps805]

Pronounced 'meat d eye'

[@official-obama]

@@flaps805 no

[@playingweirdo4720]

But this video has no explosions🥺

[@stardust857]

EE undergrad here, thanks for all of your videos, it's really helpful for understanding the concepts in deep.

[@trapper1211]

the whole 2:09 section was genius, I love it The simplified graphics have always been very confusing to me, only onceI saw the real cross section of a transistor I finally understood how they work

[@sudocheese]

I was totally panicing at first.

[@robinsparrow1618]

you remembered? >:0

[@CD4017BE]

The simplified transistor schematics makes more sense if you view the two back to back diodes as optically coupled LEDs / photo-diodes. So every every electron that crosses the Base-Emitter diode emits a photon. These photons travel over to the Base-Emitter diode to get absorbed and each allow one electron to cross its PN-junction as reverse current. If you take this model, then the current amplification factor of the transistor inversely depends on the percentage of photons that get lost during the process (about 0.5% for a typical hfe of 200).

[@NathanSweet]

@@CD4017BE "These photons travel over to the Base-Emitter" did you mean Base-Collector in this sentence?

[@lennonmclean]

DONT LOOK AT THE CROSS SECTION

[@UnicornAdvisory]

Thanks brother. Always putting out the best content since I found you in 2017. Cheers from Canada

[@MitchellClark]

This comes at the perfect time. My electronics class is going over these in a few weeks. Thanks Mehdi!

[@RieMUisthegoaT]

bad timing for me as i just finished my electronics and electronics lab haha, at least i have a good overview now

[@spectra5029]

It was also not the best time, I just had my electronics exam xD

[@veselinmanev8895]

Who has BJT's at uni anymore?

[@arwlyx]

Same, we're on FETs now c:

[@matthewduphily5129]

I started them the day he posted this, so this is perfect

[@BayEmirkiYT]

I'm waiting for "how mosfet works"...

[@catalintimofti1117]

That works off my tears because i have to learn how it works

[@unclesam6168]

Awesome vid Mehdi, please never be discouraged by lower view counts on your more educational videos as they are so high quality, and the view count should not matter to you as you are clearly so passionate about educating people about electronics in your own deranged way :P

[@uvtube2008]

To true Electrical engineers, his videos are like music from heaven. I regularly recommend his videos to practicing engineers and technicians to get things done much better than they would otherwise.

[@Autumn_Sunrise]

My 10 year old son watches your videos because he’s very into electricity and how it works! So I subscribed myself. Thank you for teaching my future electrician!

[@masonhammers9497]

Currently in a coarse largely focused on MOSFETs and it was just lovely learning that the BJT's equivalent of a MOSFET's saturation region is called it's active region. Then to double down on the confusion, they called the linear/triode region of a MOSFET a BJT's saturation region. Ahhh I love electrical engineering.

[@kensmith5694]

IGBTs make it even more confusing. Isolated Gate Bipolar Transistors are really like a MOSFET driving a bipolar of the opposite gender. They, however tend not to be labeled that way.

[@agalah408]

Sounds like it was a coarse course.

[@beewyka819]

god that was a headache when i first learned about this shit

[@Zaros262]

Lol yeah. Personally, I think it's always clear to refer to the triode/saturation region as "linear" for both types and say "saturation"/"active" for FET/BJT Context helps a lot, though. Not sure I've ever encountered a situation where the term "saturation" actually caused ambiguity

[@monad_tcp]

hum, so that's why my mosfet exploded when I tried to use it as a BJT the other day, lol

[@xdeathstar]

I am a master's degree student at Technical University of Cluj and this explanations are really really good as a base to better understand transistors. I am amazed how you evaded all the theory and explained really plain and simple a difficult topic. I'm glad I subscribed to you, thank you Electroboom :D

[@markcarneiro]

watched this full video. only remembered the micheal jackson part😆

[@davidtruelove5022]

Thank you! I recently had an issue with a pnp bjt that was supposed to a npn I just flipped it and everything started to work. Thanks for the 101 series. These are great refreshers even for experienced technicians

[@KirbzYyY]

After failing my analogue circuits class (which is BJTs, MOSFETs, OP amps and filters), this 14min video explained BJT better to me than the prof did. I knew beforehand how to calculate the base and collector current, and all the other things we needed, but I now *understand* a lot more.

[@iFATE91]

I'm curious what type of transistors are these? Common base/collector/emitter

[@Inquisite1031]

that's what happens when u are more of a visual learner, college professors often rely too much on maths and text, and not show diagrams too much to help students visualize things, and they can be hard to follow I still remember my class on Multi Variable Calculus where my friends struggled so hard to visualize the functions and the partial derivatives, when a a simple graph plotted using a computer would have fixed that problem easily.

[@dennismunyaka6537]

@@Inquisite1031 haha yes watching this has helped me to. its currently 7:00 am and I have an exam on this topic at 2:00 pm. will updateafter exam. but it did indeed help understand how it works.

[@christophpoll784]

I m a mechanical engineer. I subscribed because I love things getting blown up, and your free-energy-rant! I have no idea what to do with this transistor-stuff. But at least I know: that is all black magic to me!

[@khushvendrabissa2031]

The diode equivalent of the NPN transistor at 1:52 is incorrect I guess.... The bottom diode should be reversed to bring the n side down and to make it "NPN" BTW nice video as always sir Mehdi ☺

[@user-yb4ok1xd1p]

finally a proof that i was not alone

[@danek_hren]

Yep, you're right

[@mikekelly7862]

That was perfect; i tried to take a screenshot of that NPN cross section and then you told me not to look at it... ended up with a screenshot of your eyes instead. Seriously though, thanks EB; you've made my first year of tech school way easier ❤

[@johnaweiss]

1:22 Omg, proof that you use a green screen! I knew your background was fake. I mean, you never actually go back there and touch things. So, if your background is a projection, how do i know your foreground isn't also a projection? How do i know you're not a projection? How do i know i'm not a projection? How do i know the person reading this is not a projection? We must face the horror. We are just the tiny plaything of an alien species, who toy with the quantum fabric of space and time as we toy with BJT's.

[@interestgainer9801]

I did have a exam and I was fed up that I could not make the syllabus complete so let's watch some video on KZbin and then I started to see electroboom video what I love all time and my whole chapter is clear now with this video

[@berniefranks4876]

I have never been so fascinated with a subject I knew nothing about. I wish I had a teacher like you when I was young Thank you!!

[@ChristieNel]

This is what I needed at the start of my electronic engineering classes. Now do small- vs large signal models.

[@PlasmaChannel]

Haha oh lordy, i've never been so willing to be slapped. Good video Mehdi!

[@joelstyer5792]

This is the most well put together and practical BJT video I have ever seen. Well done! I like how you pointed out in that most applications, we only want to know how to use the device, not every intricate detail on how it works. You created an excellent balance on those two items. But what I remember most is that capacitors are the king of pop. Hilarious.

[@xTerminatorAndy]

Well done Mehdi. if a bjt is like 2 diodes, can you make a FULL BRIDGE RECTIFIER with BJT's if you don't have a bridge or diodes handy?

[@ElectroBOOM]

Hehe! Interesting thought! They are not exactly equivalent in behavior, maybe I should try it. I would need to pair an npn and a pnp

[@JustPyroYT]

@@ElectroBOOM i would like to see that! :D

[@jhoughjr1]

@@ElectroBOOM the question is will it be an amplifier or an oscillator? Transistors like tow be fluid like that the more of them there are

[@windowsxpmemesandstufflol]

@@ElectroBOOM ooo

[@subhadepdas]

@@ElectroBOOM sir please make an video on freewheeling diode

[@zenddarkson]

Do you have any Idea how much I needed this video 6 months ago? 😂

[@6754bettkitty]

0:10 Capacitor: the king of "pop" 🤣

[@johnrychlomboy1479]

Thank you for explaining it clearly!!! btw you really look like chess grandmaster Kasparov

[@johnslugger]

*Please show how to use an IGBT for high amperage power switching like BIG Battery to AC power inverters.*

[@jeromearenas8028]

More topics on transistors please. hehe Miss my college days.

[@jonlukewest4633]

This is exactly the BJT overview I needed. Thank you

[@andrewwwmnt]

You explain it better than my electronics teacher at College😂 And it's also the exact same information

[@erinc1376]

I want to thank you because your videos are what peaked my interest in all things electrical, and now I’m pursuing a successful career as an electrician and I’m the happiest I’ve ever been

[@stargazer7644]

It piqued your interest. Protect your back and don't electrocute yourself.

[@ruthstimetodraw8008]

me irl:*takes pencil and a notebook with a hard cover and starts writing down whatever he writes on the whiteboard*

[@Thatoneperson1977]

This video couldn't be timed more perfectly! I have an exam on transistors coming up in a week. Thank you so so much you make everything so much easier

[@benjaminpittelkau5410]

PLEASE cover RLC circuits (circuit analysis to get transient equations). If you teach transistors this well I might be saved from RLC in my EE class!!

[@mandarbamane4268]

V(t) = Vf + (Vi - Vf)*e^(-t/T) Vi : initital voltage (before switching when inductor is short and/or capacitor is open) Vf : final voltage (after switching when inductor is short and/or capacitor is open in steady state) t : Time in seconds T : Time constant T = L/R for inductive network T = R*C for capacitive network Use Thevenin's theorem to simplify the networks Vth = open circuit voltage when load removed Rth = resistance seen with load removed when sources are replaced with internal resistance Keep these equations in mind (comes after solving the 1st order differential equation, hence valid for 1st order systems i.e. systems with just 1 inductor or just 1 capacitor)

[@Soloist1983]

This made a ton of sense! Oddly, I now see the similarities between how vacuum tubes and transistors work

[@PetraKann]

Fleming patented the thermionic diode, the first practical vacuum tube electronic device, in Britain in 1904.

[@triffid0hunter]

@@PetraKann And Lilienfeld patented (US 1745175) the field effect transistor in 1925 - funny to think there's barely 20 years between the invention of the vacuum tube and the transistor!

[@Soloist1983]

@@triffid0hunter Wow, and it took us that long to adopt transistors?

[@ShaunieDale]

@@Soloist1983 not that long to adopt, Just that long to make them work!

[@SomeDudeInBaltimore]

@@Soloist1983 Just because the idea was patented doesn't mean there was a working one yet. They knew the potential of semiconductors from theories, but they spent that long making silicon and germanium sandwiches in a thousand different ways until the guys at Bell Labs finally did it. Kinda like how we know fusion works but don't have a commercial fusion power plant yet.

[@AstrosElectronicsLab]

Also, I know you're trying to dumb it down a bit, but you missed Hfe refers to the gain of the transistor, the SOA (safe operating area) so thermal run-away is a bad thing and that they DO NOT like being short circuited.

[@adriano2737]

1:11 🤨🤨🤨

[@TylerTMG]

whats the t mean?????

[@TylerTMG]

blow job ??????? trainer? tester? team? what would it be

[@somethingclever9975]

I wanna see this guy build a computer using his own wiring instead of the store bought wires that connect to everything

[@LordHonkInc]

Honestly, yes, this series (along with your other videos) has helped me tremendously in getting comfortable with small-scale electronics repairs. I'm still comfortably scared of high voltage stuff, but yeah, you've saved a lot of remotes, loudspeakers and the like from getting thrown out when it was easy to fix them; even hand-soldered my own keyboard after finally understanding how diodes work. So thank you a ton for all this free knowledge :)

[@1sword4you]

Do a Joule thief circuit involving a transistor and explain the how and why it works

[@025Shivam]

Video on MOSFET please DADDY!!

[@aqeelkirmani7391]

"Capacitors are king of pop" That was actually smart 😎

[@mikewillmitch3579]

I just want to thank you for making these. It's been 11 years since I got my EE degree and these are nice refreshers.

[@mohibullah6215]

can't wait for advanced topics

[@F900_Gaming]

Mehdi, I was your your 962nd subscriber, I have never left you or your videos, they've educated me so much and I thank you for that 👍

[@jedithusnbixby2108]

When this account was made a year ago...

[@digitalchaos1980]

@@jedithusnbixby2108 I'd wager they probably meant 962,000th subscriber. Sounds more plausible.

[@F900_Gaming]

@@jedithusnbixby2108 Bro, not on this account, I have a main account that was the 962nd subscriber of electroboom. Sorry for any misunderstanding

[@KenTheSteak]

Now thats what i call a brilliant segway! go learn Linus!

[@elliethebat4761]

as an electrical engineer, its fun watching you explain this stuff in a different way to how I learned it

[@kishore4733]

you editing is damn , hats off to the editor

[@TheSoldercreeper]

I wish I had both the diodes and transistors videos back then at my fourh semester. Would've helped me a lot

[@TheDecree93]

This was cool vid that made me feel smart

[@prvashisht]

OMG! How did you read my mind?? I just started looking for videos to understand BJTs and MOSFETs today and here you are! Thank you so much for this.

[@alessandrobaca8124]

I really liked it! Please continue, i would appreaciate a series about audio amplifiers. I would like to try out different circuit architectures on various levels of complexity. Awesome channel, as always. Let's also throw in MOSFETs and IGBTs.

[@Indrakusuma_a]

Wait, you can use a speaker as a microphone? o.0 After all these years following this channel, I still don't understand a thing about electricity, yet I just keep coming back even rewatching the whole videos. But hey, at least I remember a name or two related electricity now ;D

[@hugoromeyn4582]

Yes. And you can use a microphone as a tiny speaker. Just like you can use a motor as a dynamo. Does it work perfectly? No, but it works.

[@mortezazamani3570]

that was so so helpful in my age

[@GeekRedux]

A better explanation of basic meanings and functions in 14 minutes than I got in 3 lectures of my EE program.

[@ChibunduUmeh]

This was a class

[@davec8385]

These videos continue to be fantastic for concisely teaching electrical circuits! Thank you for making them, I hope you have a fantastic rest of your day

[@peterpalka4930]

Awesome content Mehdi

[@joelsmith5624]

Mehdi! You explained this better than any of my Engineering professors throughout me entire degree. I appreciate the refresher 🙌🏻

[@phonotical]

You covered this so ready didn't you?,😴

[@cosmefulanito5933]

Brilliant 10 minute video that explains the basics. Excellently explained. Congratulations. I would have loved to have you as a teacher at school.

[@lemon_plus]

looking forward for diac/triac video.

[@bupi.]

Petition to continue this Electroboom101 series.

[@erwinrogoza614]

Okay, so next video will be a valve tubes explained and a valve tube amplifier video?

[@fliper975]

I've already watched this 3 times. No matter how many times my tiny brain gets an explanation on transistors I still think it's just magic.

[@tlatitude8586]

I slowed it down to .75 speed for a viewing and also recreated the drawings. I think it is helping a lot with the understanding, but I haven't finished yet.

[@fliper975]

@@tlatitude8586 I understand what they do, and how to use them. I just don't (fully) understand HOW they actually work. That diagram he threw up was actually something I haven't ever seen and made the internal layout make more sense

[@fliper975]

@@tlatitude8586 the understanding will come for both of us at some point. This is a great video

[@vinevicious]

@@fliper975 to really understand that you need to study solid state (and for that you need to know quantum mechanics)

[@DeShark88]

​@@vinevicious I'm not sure quantum mechanics is strictly a requirement. It helps explain what a band gap is and some stuff about majority/minority charge carriers, but really no-one is solving Schrödinger equations (or more accurately quantum electrodynamics vector field equations) for this stuff. It generally boils down to classic electrostatics for the most part.

[@theyouproject]

BJT stands for what. finish it, man i like this guy he's so funny

[@aditya.21]

Hey Mehdi ! Love your videos and your style of explaining things

[@lennchma]

4:04 You said 0.5 miliamps but acutally there is a reading in VOLTS. Also later mentioned "base current" in mA are wrong.

[@davefaust7317]

I earned an electronic engineering degree in '96 but the section on transistors was taught by a guy who was unfortunately on his way out so none of us in that particular class quite got it. This has been the best explanation I've heard since.

[@zaynnxenonn2334]

It is a very good video, thank you ! :3

[@mrknownvalue1882]

I want to study electrical engineering in UG , Sir your videos are really helpfull 🙏🏻

[@lostguy362]

Jee ?

[@crazyexperiment8811]

Sir love from Bangladesh 💕

[@davidpanic]

That was a very good explanation, good job Mehdi!

[@iamboredfor2months]

THE VIDEO JUST RELEASED-

[@varshithgamer90]

How the fuck

[@agl0d16]

Wait hol up-is this cuz of patreon?

[@pyroteamfrankenjunior]

@@iamboredfor2months yes and the comment is a day old

[@your_average_cultured_dude]

@@iamboredfor2months maybe the patreon supporters get a link to the unlisted video a day earlier than everyone else

[@JonDeth]

*What was truly awkward for me is I started with dual op-amps about 6 years before I went to school for engineering, and in those 6 years, I had learned very little.* This rewinds a full 20 years when online resources were terrible, and electronics forums were dominated by rather nasty people and youtube videos were a pathetic joke. Finally, after about 2-3 years someone showed me a voltage splitter-charge pump for a single ended power supply to run my op-amp circuit, I was fed up and found a local college to enroll in. *The success is the best revenge was somewhat applicable though because after 3 months of schoolwork, I saw that a lot of well-respected people on forums explaining things had no F'ing clue what they were talking about! lmao!* They had a decent grasp on topology but none of the physics were correct nor a lot of explanations and descriptions they gave. *These buttholes would have people worshiping them to get help designing and building.* *The gratification of surpassing these dimwits was monumental and the genuinely educated people that also once belittled me no longer could.* I really wish I had started with transistors though because when I went to school, I thought I knew "basic electronics" haha not really.

[@devilette]

Wow this couldn't have come at a better time! I'm currently being held at gunpoint being forced to describe the operation of BJT transistors! Thanks Mehdi!

[@bigul_siwach]

Samajh nahi aaya par sunke acha laga ❤️

[@yashrajshinde1085]

0:12 good one...!

[@juancoetzee4181]

Please make a video of IGBT'S

[@Robbedoes2]

I know enough about Metal Oxide Semiconductor Field Effect Transistors, but this video was pretty interesting and full of explaination about unclear parts of the oldskool transistor

[@eliasagustin2]

thtanks! I need it

[@MuhammadNaveedRaza-f2v]

Sir your teaching method Please can you dubbed these type lectures in hindi or urdu language

[@IO-_-Ol]

1:58 the figure has a slight mistake. But he does explain how it is back to back.

[@alexanderbeauregarde]

I’d pay to have this guy as my Electronics teacher at school

[@hunterdedman3837]

I just noticed your white board is upside down, now I can’t stop looking at the upside down “staples”

[@KetogenicGuitars]

I have hard time remembering things. So I can remember the diode from that symbol as horn blowing electrons and that way I know what is going on with it. I wonder if at 1:53 that lower diode of the NPN should point other way around(back to back) like being symmetrically opposite with PNP?

[@baibhavpalit1085]

8:12....i guess it should be "Trial and Boom"....

[@jeremey2072]

When I was taking basic electronics in the Navy, they taught us a simple way to figure out if it was a NPN or PNP transistor on the schematic. “Not pointing in” (NPN) or “pointing in” (PNP)

[@SparkeyAvalon]

Watching this video the second time now and I understood almost nothing... :| And I'm supposed to know everything about transistors and how they work. For my work.

[@hinternsaubachel5109]

Your abbreviation for Volt looks like a root operator.

[@brad8122]

1:56 -- the direction of the bottom diode on the NPN is wrong.

[@stuffthings9618]

"That cross section cant hurt you" Thanks I needed this.

[@ishaantopkar]

I was always told that transistors "amplify" current, is that true, do they actually "increase" current? How does current increase if Voltage and Resistance remain constant?

[@austayo]

You should totally make a 2kW Class-AB amplifier. Try using the MJL21194 and MJL21193 transistors.

[@milespeterson5049]

So does this mean you can just make a transistor with two diodes? is it really that easy?

[@RC_Aviator]

If I had teachers like you in school i would have had straight A++'s

[@pennamebic5262]

I recommend engineering students see your videos before they study transistors. Your explanations gives the students a real intuitive feel for the physics. The detailed semiconductor physics and mathematics I studied were actually quite abstract and honestly after years as an engineer were not as useful as your excellent examples. The minute differences in transistor fabrication and models is best learned after your introductions. Your doing a great job.