Dammit, I wish the internet was around when I was in school!! You kids are sooo lucky to have all this knowledge available instantly! --OldGuy :)

@gojohnnygo6869

4 жыл бұрын

I've been thinking that for years. I wanted to understand and know how to do many things while in my youth but had no available quick easy answers like now. This guy basically covered a 50 page chapter in 20 min without going to the library first. This information would have taken most of a day to learn, if I found the right book. Having someone explain and show examples is so much better than reading about it. Kids these days have no idea how much easier it is to acquire information today compared to 25+ years ago.

@j3s0n

4 жыл бұрын

Humble boomer brag

@christianam9951

4 жыл бұрын

Yeah, but now they use it just to watch non educational stuff !!!

@raybin6873

3 жыл бұрын

C'mon now! Radio Shack had a "101 Electronic Circuits You Can Build " book you could buy...Healthkit offered radio controlling stuff (RC airplanes) and amplifiers...remember the ol' crystal radio? - I built one using thin lacquer coated copper wire, a simple crystal, a empty toilet paper cardboard tube, cheap low power earplug type headphones and a long piece of wire for antenna...it actually worked too..1965! (Crystal radio plans probably somewhere found on YT.) Aah yes..the good ol' days! Truth be - it's much better these days....so all you kids out there...you're spoiled rotten! Ha ha ha! 😉

@daraa151

3 жыл бұрын

Yead for my essays had to rely on library, when i go to library the book i want is already has been borrowed😏

I’ve watched dozens of transistor vids looking for exactly this info and none of the others put it so plainly and comprehensive. Thank you.

I've never watched a video that was as informative and clear. Your explanations are complete without getting overly complicated. Thank you so much for making these.

@DupczacyBawol

7 жыл бұрын

PNP transistors especially, or transistor power that is used a little to warm up the transistor, so using Ohm Law is not 100% accurate :P.

@danmick8645

6 жыл бұрын

your comment makes no sense....wanna take another run at it?

@flyjamaicanz

6 жыл бұрын

lol......great video mate, very well explained.

@glennsprigg2378

6 жыл бұрын

"Power used to 'warm-up' the transistor" ?? The .7V loss through the Base/Emitter calculation, is a bit more complex than, but 'like' the typical .6V loss through a forward-biased diode. At such 'PN' junctions, the 'P'-type having a deficiency of Electrons, and so having 'Free-Holes'. The 'N'-type has an excess of Electrons ! (I'm keeping it simple here...). Now where they are physically touching, (and no voltage applied), for so many atoms thick in the lattice some of the excess flows into the deficiency, creating an Insulating barrier at the physical junction ! As a result, even when 'Forward-Biased' from a voltage source, a Diode needs at least about .6V just to break down this barrier, before it starts to conduct, so you will always loose this! A similar effect(s) are going on inside most typical Transistors. (Hence his '.7V' loss in his calcs). (1) For a Diode, this voltage loss is NOT dependent on the LOAD after the Diode! So for example, you could connect 5 diodes in series, for a precise 3V drop, or 10 in series for a 6V drop, irrespective of the load !! (2) This 'Insulating' barrier at the PN junction, can be considered the 'Dielectric' of a capacitor, so our Diode is ALSO a Capacitor, with the 'plates' being the P/N materials area themselves. NOW it get's interesting though!! as the higher the 'REVERSE-Bias' voltage across the Diode, this FORCES an even LARGER non-conducting 'neutralized' gap/barrier. 2 main things control capacitance.... The area of the 'plates', and the 'space' (dielectric) between them. So what do we have now??? A solid-state Voltage-Dependant Variable-Capacitor !!! Yep... and it is utilized a lot these days..... although now 'Special' Diodes are made to take advantage of this effect, called 'VariCap-Diodes'. Sorry about all that... :-) I just get 'excited' playing with software like 'Circuit Wizard', that allows you to design on screen virtually any electronic circuit including virtually all elect/electronic components & IC's, see it all run in REAL time, monitor ALL voltages & currents from ANYWHERE in the circuit simply by mouse movements. Not to mention auto creation of your PCB & all artwork when you are ready, with auto track routing. ALL before you touch your soldering (not the American 'soddering' :-) ) Iron. Have fun !!!

@piskuljkopisljkuljkovic5294

6 жыл бұрын

There are several components to learning electronics. One place I found that succeeds in merging these is the Gregs Electro Blog (check it out on google) without a doubt the no.1 course that I've heard of. Check out this amazing site.

This video should be shown to everybody starting electronics... No talk of doping and PN junctions, show them this first so that they get a picture of what they are doing.. Too many electronics courses start at the microscopic level.

@EdwinFairchild

6 жыл бұрын

JonathanAnon because those courses are made for engineers . For hobbyists this is probably enough. For an engineer this is not enough.

@jabl

5 жыл бұрын

Even engineers would benefit of easier introduction to the matter.

@curiosity551

5 жыл бұрын

@@EdwinFairchild But the introduction at microscopic level kinda kills the interest in my opinion. I like to develop interest in something before getting started.

@EdwinFairchild

5 жыл бұрын

@@curiosity551 thats what i mean, if interest is the issue which implies a hobbyist, then ignoring the physics part of it is just fine. For an engineering perspective you dont have the luxury of interest, you NEED to know the intricacies whether they interest you or not.

@deegee3142

5 жыл бұрын

@@EdwinFairchild if you know it all, why are you here?

When the transistor turns off, current flowing through the coil will cause a voltage rise on the collector. If the voltage rise is high enough to turn on the diode, current will flow through the diode and limit the voltage at the collector. The problem is that the diode cannot turn on instantly. It takes time for the diode to start flowing current. The capacitor smooths out the rising voltage, and gives time for the diode to start conducting.

@pstark4

4 жыл бұрын

Applied Science that part was curious, I was wondering why the diode feeds it back, wikipedia said it feeds the back emf back into the solenoid to lessen the change in current it experiences when turned off, love it.

@yoramstein

4 жыл бұрын

With the capacitor it make sence. But in all my life I never saw that capacitor to ground in Relay circuit. i red the use fast diode or low threshold voltage diode (Shotky?)

@gondala

3 жыл бұрын

schottky diode will just fine.

@theoldbigmoose

3 жыл бұрын

Your 5 volt input may have been solid between ground and +5v. I always put a 47K from base to emitter to deal with any leakage currents if the input is inadvertently left open, either by design, or by a failure mode.

@figadodeporco

3 жыл бұрын

amazing video mate! but, could you tell us what diode should we use for this clamp?

For 30 years I've seen explanations of how to use a transistor and never "gotten" it. Bravo this is spectacular. The best explanation of a bipolar transistor I have ever seen in any medium.

Electronics engineers are probably the worlds ultimate nerds when it comes to studying such a highly complex subject ..well done..

@2:54 Your description of the circuit symbols for NPN vs PNP BJTs is so ridiculously simple and intuitive @7:00 So THAT'S what hFE is used for with BJTs! This whole video is so informative it's helped me to make tons of sense of how BJTs work. You, sir, are a genius.

I wasted weeks learning all you say in here, which I could have learned in ~20 minutes. Great video. Please add more tags to it, so you rate higher in search results.

How I wish I had friends as smart as this guy in my circle. I love channels that pass along wisdom to others....thank you, Sir!

Best explanation of transistors that I have encountered.

As someone who routinely removes protection diodes, I appreciated the detailed explanation of the relay inducance pulse. I may leave a few more diodes in my circuits now :)

Clear and well-presented. Amazingly, this circuit was pretty much the same as when I started studying electronics back in 1975, including the 2222 transistor! So for you younger students, the techniques outlined in this video will practically never become obsolete. We tend to think that the world is run on low-voltage, low-current technology (e.g. microprocessors, microcontrollers). But at some point real work requires higher voltages and/or higher currents, so studying transistor control circuits, like the one presented here, is very valuable knowledge.

Thank you, thank you, thank you, for mentioning the 0.7 volt drop across the base-emitter junction, when calculating the base resistor. I see many people forgetting to subtract that 0.7 volts. When using 5 volts to drive the base, forgetting that 0.7 volt drop across the base-emitter junction will create a 14% error, when calculating the base resistor. That’s more than enough to prevent the transistor from switching properly. Also, for the beginners, when he talks about the “clamping diode”, it’s worth mentioning that it goes by many different names. You’ll hear terms such as, “kickback diode”, “buck diode”, “flyback diode”, etc. They are just different names, for the same diode. Use a good diode, as well. One of the most popular silicon diodes, which I recommend, is the 1N4007. Actually, the MOST common one is the 1N4001, but it’s rated for much lower voltage. The difference in price, between the 1N4001 and 1N4007 is so negligible, that it’s worth just buying 1N4007’s. That way, you’ll be covered for any voltage that you’re likely to come across. It also provides an extra safety margin. In a “clamping” application, a failed diode will typically fail ‘shorted’, which will burn up your switching transistor, as well. It’s definitely worth spending an extra penny, for the better diode.

@Spark-Hole

5 жыл бұрын

1N4007 has higher forward voltage than 1N4001. 1N4007 waste more energy to operate... Same thing happens to higher voltage transister. So not a good idea to choose higher rating voltage than it needs to be. PS.....Also I have heard word "free wheel diode"

@Asyss_Complex

5 жыл бұрын

ຮຸ່ງ ພຸ່ງແຣງ So what would be the best way to protect the transistors if picking a higher value diode is not efficient?

@RexxSchneider

Жыл бұрын

@@Asyss_Complex The Fairchild (On Semi) 2014 datasheet for the 1N4001-1N4007 series specifies the same forward voltage of 1.1V at 1.0A for the entire range. In addition, the energy dissipated in the diode is not a consideration in these sort of applications unless you're trying to switch the solenoid at kilohertz frequencies (!), so it doesn't really matter which diode you use.

Eleven years ago... Still extremely well done and very valid.

over 8 years later and this video is still one of the best practical examples of BJTs

So clear. So lucid. This is a great switching transistor 101. Thanks, really appreciate the work you put into this.

Best transistor tutorial I've seen yet. Thanks alot!

the best explanation on the topic that I've found.

This is what engineering is about .. something complex and making it simple.... thank you

This gave me the understanding I needed to figure out a circuit I was banging my head against. Thank you!

@billgreen7283

3 жыл бұрын

Don't damage the circuit with your hard head.....lol

Thank you so much. I've spent ages trying to learn this basic theory and you have explained it wonderfully. I now feel I can grab some components and use them to switch real world items from an arduino. Fantastic video!!!

I knew much of that but learned more from this. Learning is why I watch the videos. THANK YOU!

Nice job. I was trained as an EE, and in the lab I blew up dozens of 2N2222 transistors. Later, as an "advanced" student, I destroyed a few Op Amps before I got the hang of their biasing. In the late 1970's, a simple NPN transistor was inexpensive - maybe 25 cents at the school lab stock room. Op Amps were much more expensive in the 1970's -- maybe a couple of dollars -- so I learned to read the data sheet carefully before breadboarding those projects. When in doubt, add a resistor! It's a good motto for any EE student or dabbler in the mysteries of electronics. One of the most valuable circuits a designer should know by heart is the voltage divider. Such a simple circuit, and so many fresh faces in the lab don't know it. Lesson 2, a little more complicated, is using a negative feedback circuit to automatically control current surging at the base and thought the transistor. Always protect your active components! I appreciated your trick to sink stored current around the solenoid, too. Thanks again. I'm retired and haven't played with electronics in a long time. I've been looking around KZread for interesting channels. and yours is practical without being pedantic. I'm a new member and will be looking in.

It took me years to learn this by myself when i was a young electronic enthusiast. You summarized nicely, and totally understandable. Great job!

@saneeshelectronica9293

4 жыл бұрын

See my vedio on transistor ckt design

You are a life saver. Thank you for that explanation, it solved some questions that I had in my mind. It's nice to know why I am doing certain things instead of blindly following equations. Thanks.

I have searched the whole internet and the the things I was looking for are packed here in this 20 mins video .. excellent video

So simple topic ..... But you inserted a universe of knowledge.... Great explanation.....Great love towards the subject.... Finally... simple topic is where the research starts... The world should know this.....

Good Tutorial. Thank you for that. Just another thing: You have to consider the power dissipation of the transistor itself, due to the voltage drops across it. taking the numbers (0.2Volts and 56mA), you can say that the transistor dissipates like 11mW of power, which is quite low for that circuit, but if you have a larger current and also a larger voltage drops on the transistor, you could damage your transistor if you don't attach it to a proper heatsink.

Very nice explanation. Super clear and concise primer on transistor basics. I was glad you skipped all the ohms law and such and just got right to the setup and calcs needed to drive your load. All the rest of the blanks can be filled in from innumerable other sources across the net. Excellent job!!!

Best explanation video on simple use of transistors in DC circuit so far...

168 dislikes from PNP transistor fans? Such an amazing tutorial explained in the simplest way imaginable!

Thanks. Your experience shows and this makes me feel confident about your lecture. As my brother says: in theory practice and theory is the same but in practice it's not.

Why couldn't I have had you as my electrical theory teacher. What I learned in 21 minutes with you took me weeks with my teacher....and I probably still did not quite digest and assimilate it well enough. Thank you for your tutorials and lectures. You are educating the world.

Just what I needed - Transistors are a simple yet madding concept that pushed me to look for a tutorial to get back to basics. Found exactly what I was looking for!

After many classes at University learning about transistors, this is where I actually understood how one works!

Really a great video! Clear and simple! Thank you!

@GianmarioMarchini

9 жыл бұрын

cos è sta supercazzola? ...hai il dono della sintesi? me la riassumi? :)

@PaoloTamburini

9 жыл бұрын

La cultura non è per tutti!! 😜

@GianmarioMarchini

9 жыл бұрын

a hahaha....preparati per la stagione venatoria che siamo a brucio vah!!!

First year electrical engineer student. Thanks for this video, I think you are a great tutor.

I'm only half way through the clip, and I have to say: thank you for teaching me the difference between NPNs and PNPs! Also clears up as to why my electronics project failed, as I was not given the distinction that they are different and as to what the difference is. The irony is, it's simple! I guess the teacher needed a break.

@SianaGearz

7 жыл бұрын

Starting with the age of about 16, most education systems require a bit of own initiative to acquire knowledge on their own on the part of the student (like at least asking questions in case something isn't entirely clear), as that is really considered the most important task of mandatory education, rather than simply conveying knowledge. But it might not be the case where you live, which begs the question, how would that kind of school system prepare people for college or university at all?

Very good tutorial about designing a circuit by using transistor, put more about this topic very interesting to watch and learn

Absolutely fantastic tutorial!

You are a great teacher! Thank you!

@bikashdas1182

6 жыл бұрын

Perfectly done

@fernandovelasco5632

6 жыл бұрын

Just a curious question. Why is your current flow in reverse? Current flows from negative to positive

@EdwinFairchild

6 жыл бұрын

fernando velasco mathematically it makes no difference which way current flows. Most people use conventional current flow over electron flow

@jonka1

5 жыл бұрын

Yes it does but he is talking about CONVENTIONAL CURRENT FLOW where it is imagined that current flows from + to -

@chandrakumargurung7034

4 жыл бұрын

I ve deep interest in electronics i want to learn more...

I learnt alot from this video ,well shown and explained ,and i am 65yrs and still learning ,Wish i had someone like this to teach me in my younger days .Many thanks .

The best video I've ever seen about transistors.

Wow, great job on the video. I'm not too good with electronics, having learned strictly with MCU's early on and using digital PWM instead of actual power management. You have nearly tripled my knowledge on transistors and how they can be used, and for that, I thank you.

@v2point0

9 жыл бұрын

Same here :)

REALLY good video. Probably the best transistor video I've watched. Nice job!

Learned more in these few minutes than in the hours I spent on my own to clearly understand these principles. Many thanks and cheers from Florida.

Great tutorial. I know the feeling of blowing things up through a lack of knowledge: I destroyed two "5v" LCD screens instantly, it turned out the backlight was 5V, but the control was 3.3V.

That was wicked awesome man, thanks a bunch.

Thanks for the great tutorial. I wish you would have given details about how to choose the appropriate clamping diode. Also a bit about the rol o the capacitor, and how to choose it. Also, it was unclear to me why NPN instead of PNP. I did not understand the justification.

I'm pretty sure this is the best introduction to how to practically use transistors and explanation of their essentials of how they work I've ever seen.

if i could, i would gave it 10 thumbs up. it was a very simple but complete explanation. well done

"Yeah but I live in a voltage world how do I get this solenoid to turn on and off" Legit LOL'd.

@willie_mccoy

4 жыл бұрын

Livin' the voltage life.

Finally, a way to control a motor requiring 12 V from an Arduino and L293D. :)

I have no business being here, however I stumbled upon it and watched it all the way through and I think i learned a thing or two along the way. You're a natural teacher, thanks s`much.

Excellent video. Explicit, practical, logically ordered, easy to understand , in perfect English. Short-practical- utilitarian - easy.

Actually they DO make 4.3k resistors and they're part of the E24 series (24 values per decade).

Many years ago, I came up with a way to quickly differentiate between NPN and PNP transistors. I look at the emitter arrow, and if the arrow isn’t pointing inwards, its an NPN transistor. NPN = (N)ot (P)ointing i(N)

@ajayrajan8882

5 жыл бұрын

Try to watch Razavi lectures you won't need hacks to remember that

@TheArnoldification

4 жыл бұрын

I learned the difference by just never using PNP *dabs*

@henningb2274

4 жыл бұрын

''Points the arrow to the B - it's PNP'' is another way

@tomaszwota1465

4 жыл бұрын

@@ajayrajan8882 mnemonics is not a bad method to reliably revert stuff though

Great job explaining it and showing it in practice.

I went to school to repair PCBs many years ago but in my profession I wound up doing repairs at the next level. "Through that board away and replace it". This is usually the cheapest and quickest for repairs of most equipment but that takes all the fun out of it. I still enjoy dabbling with semiconductors but time is not on my side. This great video helped me to refresh the details I need for my dabbling. Thanks, Great video!!

Back in 1979 my high school electronics teacher taught us to remember NPN = the arrow "Not Pointing iN".

@no_one1073

3 жыл бұрын

It's still the best way to remember it.

Hi :) Great video Just one question: why did you say in the beginning that the pnp doesn't have a way to limit its base current? Shouldn't a resistor work as in the case of the npn?

@avid0g

6 жыл бұрын

Andrei Stefanescu, since the logic input signal varies between 0-5V and the emitter is at +12V, the base current can never reach zero. Thus the PNP device is a poor choice here. On the other hand, if the logic -input- output varied 0-12V it would be acceptable.

@adon2424

5 жыл бұрын

@andrei, think opposite. in an npn a + voltage at the base turns it on. in a pnp a + voltage at the base turns it OFF. 12-5=7VDC across the emitter/base juction, because you have + 12vdc at the emitter.

@renakunisaki

5 жыл бұрын

@@avid0g so you would use that if you needed a 12V signal to control a 5V device?

@avid0g

5 жыл бұрын

@@renakunisaki My point was that an open collector logic device with a resistor pulling up to +12 volt would have the correct output. The logic device needs to be rated to handle the +12V. An NPN would also translate, but with inverted logic. One downside to resistor pull-up is the RC time constant rise waveform.

Clearest and most understandable video I have seen. Thank you

omigosh i have been an electronics hacker since i was a kid and i think i've never gotten such a solid grounding of how to work with a transistor. i'm 100% going to use this as a reference on my next project

I would always use a MOSFET for power control, and not a BJT. Unless I needed to control the amount of current through the device. BJTs drop voltage and waste power.

@stanimir4197

3 жыл бұрын

Absolutely. Although MOSFETs have to be driven hard(er) for higher voltages - and even in this case, they would require a pull down resistor at least (5V is high enough gate voltage for most cases to driver 12V). It's harder to explain.

@RexxSchneider

Жыл бұрын

A BJT is a perfectly reasonable choice for currents up to 100mA as the voltage drop and power wasted is then negligible. Above that, a logic-level power mosfet is a good choice, and essential if you have a 3.3V microcontroller. Remember that the mosfet will normally cost three times the price of a small-signal BJT.

So what do you guys think about biopolar transistor are they getting too old since the mosfet ones got more efficient and popular or is it just me? for all my applications I use FETs and can hardly think about using biopolar yeah FETs are a little more expensive but still the low 'ON' resistance (Efficiency) is well worth it.

@hawkcrave

7 жыл бұрын

"A little more expensive" can add up to a lot more expensive if one is building hundreds of thousands or even millions of widgets, with each widget possibly having many transistors. I would guess most companies simply go with the least expensive option that meets the requirements.

@mikelemon5109

7 жыл бұрын

Yeah but the very high efficiency translates in to a more quality product when it comes to power consumption and simplicity anyway mosfets get cheaper and cheaper over time.

@hawkcrave

7 жыл бұрын

True. It would then depend on what the requirements were, and if reaching higher efficiency is more important than reducing costs. In some cases it would be worth it, in other cases, not so much. But either way, you've made me think about it and I will do some more learning about BJTs and MOSFETs so I actually have a clue what I'm talking about lol.

@mikelemon5109

7 жыл бұрын

Yeah that would be great!

@1boobtube

7 жыл бұрын

Michael bjt transistors aren't inferior because they're older they happened to be discovered 1st. Fets are a cousin to tubes which came before that. Tubes still have their place. darpa is still pouring money into tubes. a plain old 3904 bipolar isn't going on the scrap heap any time soon.

Very well done and thorough. On par with my early lessons in college and in a couple ways a bit better.

Watched many video's on the topic, none was ever this clear. Thank you!

Nice video. The 2N2222A handles 800mA, meaning that if the restriction depends only on the transistor, the right resistor would be (5 - 0.7)*100/0.8 = 538 (560 ohms). So, the solenoid would be destroyed but not the transistor!

@curiosity551

5 жыл бұрын

What about the power loss that occurs between base emitter junction due to low resistance? Cant ignore that either.

@eelmot63

5 жыл бұрын

right what I was going to say

@AlienRelics

5 жыл бұрын

10, not 100. As a switch, base current should be 1/10th of collector current. Read the datasheet.

@kissingfrogs

5 жыл бұрын

@@AlienRelics Can't help think that Ben has been scarred by destroying many transistors when he started out that he errs on the side of minimizing base current. 1K would do the trick.

@AlienRelics

5 жыл бұрын

@@kissingfrogs Perhaps. But beta varies from batch to batch, device to device, temperature, and time. I'd accept 15 or even 20, but 100? That is the rated beta in the active region. You'll destroy more transistors with excess Vce drop at higher current.

in your circuit you need to add resistor between base and ground e.g. 100KOhm to avoid floating base Good tutorial though

@AppliedScience

9 жыл бұрын

Beboba This tutorial discusses bipolar transistors, which do not have floating bases, and do not need such a resistor. An insulated-gate transistor such as a MOSFET or IGBT have high impedance gates that may need a resistor to tie the gate high or low.

@beboba2498

9 жыл бұрын

Applied Science Interference from nearest components can easily turn the bipolar transistor on. E.g. if you have high voltage generator.

@Akfloatable

8 жыл бұрын

+Applied Science Can you explain what a floating base, or floating anything is? I see this mentioned a lot when reading about electronics.

@AppliedScience

8 жыл бұрын

+Akfloatable Leaving a pin of an electrical component not connected to anything is considered "floating". This means that the voltage at that pin can change very rapidly if there is nothing to sink or source current. Turn on a digital multimeter to its voltage range, and leave the test leads disconnected. You'll see the voltage floats around. For some components like bipolar junction transistors (BJT), leaving an input floating is not particularly bad because the device requires a fair bit of current to operate, so the pin will remain fairly stready by itself. A MOS component requires almost no current to operate so the slightest bit of charge will cause the pin voltage to change, and turn the MOS on and off very rapidly or partially, which is not good.

@JasonDoege

8 жыл бұрын

+Beboba BJTs are current activated devices (current from base to emitter establishes the current from the collector to emitter.) If the base is floating, there is nothing to induce a contiuous current from the base to the emitter, an electrostatic charge, while a very high voltage, doesn't have enough charge to induce a large enough current to turn a small signal BJT on. FETs have the issue you discuss where they are voltage activated devices (voltage between the gate and source establishes the current from source to drain) and can easily be turned on by stray voltages. All that said, very high gain BJTs (especially darlingtons) can be briefly turned on by small electrostatic charges.

I've been unsure about how a transistor is actually used for so long and nobody could really explain it, but this answered all my questions!

One of the best transistor as a switch presentations I’ve seen. Thank you.

I've got two bread boards. I can make a ham on rye on one of them.

@willie_mccoy

4 жыл бұрын

I tried that once, but the wires kept getting caught in my teeth.

What you didn't cover was how you chose your diode and which one.

@benjaminfacouchere2395

7 жыл бұрын

electronics.stackexchange.com/questions/110574/how-to-choose-a-flyback-diode-for-a-relay

I spent a few hours searching for a good explanation about this, and this video was the one who actually did it.

WOW...WOW!! Tanks a lot man. Nobody ever explained this so very well as you. Learned so much here, thanks man!

By far the most simple, complete non confusing and useful transistor lesson i have seen! Thank you... Subscription done!

this is what i expect . most of the videos simply explain the low to high but you deeply gone. thanks a lots

Thank you so much this is better than anything else I've found on transistors. I've been busy blowing out transistors all night.

This is an excellent video! Great job on explaining the thought process and the math behind your decision as well as the practical application of it.

Just what i needed. I have a design concept, but needed some practical info on sizing components. This was perfect. Thank you.

Starts by showing off all his big transistors. End up using the smallest one lol. Awesome video!

Really excellent explanation of some basic ideas around transistors! I'll get my son to watch this because he has a fear of electronics and this is pitch perfect. Thx

Thanks for that lesson. I was a mere lad when most audio electronics were tube devices. And that includes TVs. But today i enjoyed upgrading my knowledge with transistors.

I've been using npn transistors for a few years and Never fully understood why sometimes they work in my circuits and sometimes they don't. So glad I stumbled on this 9 year old video!! thanks

I love the way you explained ; illustrative and well simplified . I gave a thumb up to this video . Thanks .

So well explained. A great teacher, thank you.

Integrated Circuit designer here. To answer your question at 20:15: that is what we call "saturation" in a BJT. You need at least a few hundred mV of voltage from collector to emitter to give electrons enough energy to shoot across the bridge created by the base current. It actually takes a relatively large amount of current to re-bias a bipolar once it enters saturation, because with 0 Volts from collector to emitter, it debiases and its capacitance grows a lot. Not something to worry about for a breadboard project but a huge design consideration for ICs where speed matters.

I think i watched hundred of videos on the same subject. This is the first time that i see someone explaining every single step, all others always take those for granted. And abole all i appreciated the first part, when he described the several choices (possible components to use). All the designers make tutorials and never clear why they use a particular component among others and indeed they must know the reason (again take that for graanted). I congratulate and thank you.

Very simple, straight-forward explanation. And somehow you managed to predict all the questions I wanted to ask as I was thinking them. Excellent video!

When I first started in electronics it took me way too long to understand how transistors work. Wish I had this video when I first started. This pretty much covers everything you'd need to know about using plain BJT NPN transistors for use in DC circuits. Best and most concise explanation I've seen on the subject. Well done!

Hats of to the depth this man goes to for explanation. Amazing.

Very good explanation. Just the right amount of information for an introductory of how to use a transistor as a switch.

High Side versus Low Side switching, explained with plain words. Done very well!

Great tutorial, thank you. After searching for a while, I finally understand the meanings of things like gain and Hfe, and why a diode is important in a solenoid circuit.

That was one of the best transistor videos I have seen. Practical approach and good examples. Excellent!

You are a savior! All the other people on KZread are explaining it to fast, like it would be self explanatory or sth. Thanks!

This video is awesome, no one else has been able to answer these questions clearly for me. I also appreciate that you actually included the formulas needed to calculate the resistor needed on the base leg, etc. Great vid, thanks a ton!

I have always wondered about how this worked. Seeing you add the different components to the solution and the calculations were very clear. Thank you

Excellent tutorial. Thanks for sharing the very basics of a transistor to be used as a switch. Very nice demonstration.