Transistor / MOSFET tutorial

[@fzigunov]

When you realize this video is 8 years old and is still useful... Not many youtubers reach that level!

[@anonimuso]

But lol at "You can get a transistor from Radio Shack"...

[@Tumbleweed-vh4pt]

anonimuso if you can find a radio shack that is still open 🤔

[@lolbubs11111]

"your computer's parallel port" lol

[@chanakanirmal7298]

dame you comment brooo.. wow

[@mr.meticulous1241]

anonimuso dude that one hurt :’(

[@Afrotechmods]

Gah. Now I wish I had covered this in the video. The gate pin has a small capacitance, and will hold a voltage for many minutes with no power applied and pick up stray voltages very easily. So you should put a 100k resistor from gate to ground to discharge the gate and have the FET off by default.

[@za_ozero]

i figured it needs a pull down resistor. I wish you were posting more vids

[@idlando]

This is the most neurotransmitter efficient tutorial I've seen for a long time. Straight to the point, clear and precise. Thanks!

[@jorgewashington2981]

Thanks Afrotech. You are one of the best Electronics instructors on KZbin.

[@loverboy-if3ox]

I agree the BEST! and I have a learning disability and that says a lot thx

[@MyBigThing2010]

wow DUDE! ...this is like the 6th time I've watched this video and I just FINALLY had that "AHA Moment" where everything just aligned in my thick skull and I actually realized WTF is going on in circuits with transistors in them and how to go backwards through them in a LOGICAL way and KNOW what I'm looking at and looking for....I wish this channel had like 3 million subs and you were a full time KZbinr! your videos have spawned a few of those "oooh! that's how it works" moments for me while learning this stuff....I thought it was all alien tech that I'd never be able to learn/understand and your channel has been instrumental in helping me over hurdles...even if I don't know it while watching or feel stupid for not getting what the video was about...down the line I'll look at something and instantly revert back to the info in the video I inadvertently retained and I'll get a better grip of what I'm looking at because if that info...Afrotech University, electronics engineering school. hmmm, I wonder if that would fly if I put it on my resume? haha...nevertheless, I'll say it again. THANK YOU!

[@xXxkrispyXlolitaxXx]

i love those moments

[@dredrotten]

This is the simplest articulate and clear straightforward no BS tutorial Ive ever come across! Good on you Mate. Excellent job!

[@MsMadLemon]

You've made FETs less intimidating for me, this will help me in a project i'm currently doing, thanks! :o)

[@hardbuilder70]

Probably the best tutorial i have seen on electronics. Very well spoken and easily understood.

[@Afrotechmods]

Yes. Pulldown resistors are generally a good idea. See my PWM tutorial video.

[@StrsAmbrg]

This is the best teaching I found about N-channel MOSFET. So easy I understood. The voltage range you explained made everything complete. And the placement of silicon and zener diode made more complete.

[@deldarel]

To people thinking it's a relay. The general purpose is the same, but there are important differences 1. a relay is isolated from the circuit, but a mosfet is not. Drain and Gate share both the Source, meaning that the current of source is gate + drain. Usually this isn't too important, but be sure not to connect a fusion reactor to the gate. 2. Mosfets are much quicker. You really only want a relay at the very end of your circuit, and only use mosfets for this function within the circuit because it doesn't have a built in coil and the moving parts are much much smaller.

[@andriosz]

Can you use these to make a PWM control for a cooling fan for a car radiator ?

[@Afrotechmods]

@Xearo167 Electrical engineers work with what is called "conventional current." It is backwards to what is correctly taught in physics, but all electrical engineering laws and formulas are based on it. So for the purposes of designing circuits in EE, current flows from positive to negative.

[@Afrotechmods]

the capacitors usually go first, but once that happens all bets are off and pretty much everything is prone to failure.

[@Afrotechmods]

@HHOhybridBuilder Sort of. Varying the gate voltage from 0 to 5 will vary the drain-source resistance, which will result in the drain-source voltage changing when the FET is operated in the linear region. This is usually done in amplifier circuits and it causes a lot of heat to be generated in the fet. For switching applications you want to avoid the linear region so the FET is either high resistance or very low resistance - nothing in between.

[@PeperMintification]

Excellent video, it greatly helped sparking my interest in electronics a few years ago - I've built many toy systems with transistors since, namely my custom made power boat (that needs some maintenance)! Thanks for sharing your knowledge and spending time creating this really awesome electronics videos! Hope to see more tutorials :)

[@Afrotechmods]

3VDC is generally quite low for mosfets. It might work, but there will be noticeable resistance between drain and source (perhaps 1 ohm or more). You can get 'logic level mosfets' that switch on with very low voltages, but they are usually only good for switching 10-30V. If efficiency is not a huge concern and you just want something easy, get a TIP110 from Radio shack or any NPN power transistor. They will switch on fully with 3V no problem.

[@dagobb]

Excelent tutorial, now I can switch leds on my quadcopters and my airplanes for flying at dusk or night! THANK YOU !

[@Afrotechmods]

dagobb That sounds like a perfect application! Glad you liked it.

[@이용덕-g3k]

Afrotechmods )

[@IAMainvision]

Between Afrotechmods & RimStarOrg here on youtube there really isn't any reason to study electronics at university. Superb work! Clear, concise & accurate! Keep up the excellent posts. Cheers

[@FCADurgeshKumar]

4:05 made me to subscribe this channel. This is what i was searching. In a single video you had explained everything. Please provide direction of diode to be used with solenoid.

[@ristomatti]

I agree this is one of the best simplifications on how to use a MOSFET. Saying it explains everything you need to know would be exaggerating. For example it did not answer what do you need to do to switch loads of higher currents even though very high currents are often found in MOSFET data sheets. It's difficult to find a logic level MOSFET that can be used to switch for more than 1-2A of current. It becomes much more difficult if you want to do it with a controlling device using 3.3V logic levels such as an ESP8266 or a Raspberry Pi. When this video has been created 3.3V logic levels were not as widely used as today. In case you have not yet found the answer, Afrotechmods suggests watching this video of his in a reply to another comment made 4 years ago: kzbin.info/www/bejne/gomqpXhpjZeebbs

[@Afrotechmods]

@Bizorke For an N channel MOSFET Vgate has to be typically 3-10V higher than Vsource to turn on. The drain voltage does not factor into this, although it indirectly does when the FET is being driven high side. But for example, if Vdrain is 20V and you tried to make Vgate higher than that you might kill your FET.

[@diabloenergizer]

Best explanation i could ever find thnx

[@ten10ca]

KEEP LOOKING

[@MrBelchfire8]

Thank you for a simple explanation without annoying music or "humor". Appreciate "just the facts".

[@Flankymanga]

4:22 Can't believe my eyes... in America you had Tesla subcomponents?!?

[@TangodownNZ]

Thanks. I have watched many complex tutorials on transistors and none of them made sense to me. You explain it very well without over complicating things.

[@Trielectify]

Great informative and interesting

[@deanwesterburg]

All your tutorials are awesome! If you aren't a teacher, you should be! Your teaching style is very clear and easy to follow. You're KZbin channel has helped me a lot! Keep up the great work!

[@technosasquatchfilms]

Who the hell is down-voting free information!?

[@linkstatic12]

I am an Engineering and have alot of experience in transistors. I loved your tutorial on this. Keep up the exceptional work!!

[@hameedwafaAFG]

Hahah I like headache video

[@Aspins]

I am 62 years of age and have always wanted to undersand the fundimentals of electronics I have tried for years on and off to get my head around the why and how of it. Thanks to your tutorials the penny is slowly starting to drop. Thanks Keith

[@Afrotechmods]

It should be written on the transistor's casing. You may have to remove the heatsink to see it. You may also have to use some acetone to rub off any dirt that might be covering up the part number.

[@Apc204]

Thanks! I never really understood the N channel MOSFET in the few lessons we did about it in class. I watched this video just before my AS electronics exam and it helped me answer three questions about the MOSFET on the paper. :D

[@warcog]

Hey Afro, I have to tell you: That was probably THE most helpful thing I have found on KZbin for a couple years. THANK YOU for making that. You're a saint. I have been struggling as a hobbyist building some MOSFET switches for airsoft gun application. Fiddling without understanding of much in the way of electricity - a big handicap. Now I think I just might get it - thanks to your tutorial!

[@Afrotechmods]

@lowsideswitch Transistors can be switched faster infinitely - most relays can only be switched a few times per second and have a life of 100k cycles. Switching an N MOSFET high side will require some extra gate drive circuitry.

[@ahonda55]

Man, you are great, and what time you had trying to teach someone something will not go to waste, the world will apreciate that. THANK YOU

[@Afrotechmods]

You would need an optocoupler with a totem pole or logic output. A logic level mosfet would also be a good idea. The project should be doable.

[@Afrotechmods]

@HHOhybridBuilder yes. It turns the fet off by default by discharging the gate.

[@computerchi]

5 minutes ago I did not know a MOSFET transistor from Adam. Now I think I can easily use them. Thanks. You rock.

[@ForViewingOnly]

Afrotech, you rule! These videos go at just the right pace for my aged brain... great work! I've watched 5 of your videos in the last 45 mins. Please make more to feed my new obsession.

[@Target008]

Excellent tutorial, it is nice to see that some people don't assume that everyone already knows everything, Thank You

[@Maham899]

I am impressed by the narration and graphical description.

[@philbx1]

Wow, never saw your channel until you recently commented on eevblog's channel. Fantastic stuff, and I don't know how you do the 'voice' thing, but the combination of great dialog and straightforward tutorials I think amazing. Surely you are (or will be) a fine teacher! Thanks much.

[@Afrotechmods]

That's a more complicated question to answer but i'll simplify it... the IRFZ44 will start to turn on somewhere between 2-4V but there will still be some resistance around 1k-100k ohm. With Vgate at 5V the resistance is low enough to be useful, roughly 1 ohm. It will be 'fully' turned on with 10V and the resistance will be around 20 milliohms.

[@davidjereb]

You are awesome! Everything you explain is so easy to understand, you speak clear, proper english, so there are no problems to understand you and you have a gift for teaching. Keep these tutorials coming! Thanks! : )

[@fritzj6803]

Omg I've watched a million videos, but you got straight to the point and made it understandable.

[@LoganEdwards]

Wonderful video! Simple explanation, solid narration with a hint of humor. We need more of this in the technical world.

[@phattacorider]

The way I see it, Drain goes from the negative end of your car light bulb (opposite the side of power input), Source goes to vehicle ground or battery negative (in this example of car light bulb), and Gate is the switch, 0v for off or 5v for on, from some sort of transistor-suitable voltage. Please correct me if I'm wrong, as I've used lots of relays and have never used a transistor of this type before, but this would be a great thing to learn!

[@germas369]

FETs can be extremely complicated but im glad that videos like this exist. it simplifies the theory and its easy to put them in practice

[@Afrotechmods]

@herctrap The LED will also need a current limiting resistor as usual. But the main problem here is that the voltage between Gate and Source has to be at least 5V for the FET to turn on, which won't happen because Vsource will now be ~12v when the FET is on, so you'd need a gate voltage of 17v, which is impractically high. In other words, you need a high side gate driver circuit.

One of the best explanatory tutorial i came across. Thanks for making this video. Kind of weird i just now find it after 12 years. 😋

[@jatinmali9310]

I never skip ads in your videos and that's the least I can do for you Thank you for making such videos

[@Afrotechmods]

Aw thanks!

[@Afrotechmods]

@rainbowsalads Use a diode to convert the AC into DC then use an NPN transistor to toggle a relay which switches on the bulb. Or find a small relay with a 3VAC coil voltage.

[@Afrotechmods]

On a datasheet, the relevant graph is Rds(on) versus Id for different Vgs

[@kieferonline]

Best tutorial of all time. Afrotechmods is a gifted teacher.

[@Afrotechmods]

The circuit in the video should work (you can use the version with a relay if you want) if you add a 100k resistor between the gate and ground. This allows charge on the gate to drain to ground which will turn the mosfet off.

[@Afrotechmods]

@WINANDMACNERD Sort of. There is a small linear region (around 1-2V) on many fets that will act like a voltage controlled resistance. However you will need to DC bias your sine wave very precisely and make sure the amplitude of the wave stays within the linear region. Read up on the datasheet for RDSon versus Vgs to find the region. This will also cause the fet to heat up. You could also look into digitally controlled potentiometers.

[@betergigech]

i been looking for a clear explanation in spanish about this gadgets but i didnt find it until found this in english thank you very much is very clear and understanding

[@BadDL282]

Excellent tutorial !!! The source-drain terminology seems backwards but that's the way it is. Clear and easy to understand. Thanks

[@fc3sbob]

out of all the video's explaining transistors think this one is the best! I just got my arduino +5v to switch 24v DC Relay's.. let the fun begin!

[@mikaelsantos316]

This is the most direct video ive seen so far.. very easy to understand!

[@pcproz3215]

I really love your teaching style. You eliminate the "mystery" from the circuits. Have you ever thought of doing a "full blown" electronics tutorial? I would definitely buy it if you did. Thank you for taking the time to do these vids.

[@haczyk84]

Short and straightforward. I've seen many student of technical schools who doesn't get it. Nice video.

[@Afrotechmods]

@BadDL282 Well, the reason is sounds backwards is because if you look at it within the context of semiconductor physics, the electron flow is from source to drain, which is the opposite of the conventional current terminology that electrical engineers use.

[@BackFlash2K]

I like the bits of humor in your videos. [Subscribed]

[@Afrotechmods]

@jackwhitesguitar Yes, there is a small linear region, but that goes beyond the scope of the tutorial and most people will never apply it anyway.

[@FindingMyself90]

Thank you for such a great tutorial. I love how you went from the mosfet to other things you can switch on and off. Really helpful

[@sbreheny]

@Afrotechmods Awesome tutorial! Regarding the voltage between gate and drain - once the FET is in the ON state, the voltage on the gate does indeed need to be at least one threshold voltage higher than the DRAIN in order to make the FET FULLY ON. This is only really important when passing very large currents through the FET, where the current times the RdsON is more than 1 volt. This is the reason why it is important to drive the gate with a few volts more than the Vthreshold.

[@martinfinster9899]

Yes, great voice, nicely constructed tutorial. Sometimes the basics are assumed and these from you fill that need. Really nice job.

[@fgdfhtrhg]

Your tutorials are SO much better than the others! cheers dude

[@Afrotechmods]

@gizmoguyar You got it. Make sure you connect the grounds (a thin wire will do). The high current should be flowing through the FET. That will of course depend on where exactly you have the power wires connected. The -ve wire of your external power source should be connected directly to the FET's source pin. If you were to connect it to a ground pin on your Arduino, you can imagine the current would flow from Source-> Arduino PCB -> -ve wire which would be bad.

[@kuldiprandhawa]

Thanks Bro. I am trying to learn this thing from 12 years. you really explain so nice.

[@w3mq]

Great tutorial, I understood more about the transistor in the few minutes than i ever did in High school and College. I guess some people are better teachers than others, I'm going to watch this again and try to experiment.

[@Afrotechmods]

@sjh7132 Good comment. When driving MOSFETS in switching applications, you want to drive them hard on, or hard off. Putting a wussy 1.5V signal at the gate won't be enough to fully turn the FET on, so there will be more resistance, so there will be more heat. A good gate driver circuit will switch hard between 0V and 10V, but 5V is often enough to get the job done if you aren't switching high currents. It all depends on the specific Rds(on) versus Vgs characteristics of the FET.

[@jarekz90]

Im from Poland, this video help me to understand how to work the transistors. thank you!!

[@Mindthegap720]

This video explains quite a lot better than my professor at university. I thank you *Afrotechmods*

[@JBattler]

Thanks so much for these tutorials...you make it so simple to understand. Most on-line tutorials are very badly done....your are super. One thing I don't understand though is why you need a diode to switch a motor on or off. Obviously I am missing some important bit of info in my "database". Thanks JB

[@Afrotechmods]

No need for a mosfet driver for occasional on/off switching as done in these examples. If you are doing 50+kHz PWM then a gate driver starts becoming more useful (way beyond the scope of this tutorial). The diode is in the correct place for low side switching of inductive loads. You might be thinking of H bridges.

[@izelxx1]

I really like this; It is good, clear and well done. It explains things easily. Although MOSFETs were not the easiest thing to build. It took a lot of effort.

[@jessesinclair4491]

finally, electronics signal flow/path etc.. has elluded me for so long. the videos by this guy are explained in the right manner for me to take in. subscribed, great videos thankyou.

[@jerrychristensen6096]

Greatscott may be the buzz now but Afrotechmods will always be the OG

[@Afrotechmods]

@Jie1478 Ah that's called the 'tab' on a TO-220 packaged MOSFET. It is almost always another drain, but always double check the datasheet for your part.

[@TheMegajupiter09]

Excellent! Many who do such videos should learn from you. They miss the point of their tutorial. Your voice is also approved! Lol!

[@feralbigdog]

this video answered a question i had perfectly about which way power flows through transistors, and explained how they work better than trying to understand them on ehow and wikipedia articles

[@ubuntututorials]

Also transistors can vary the amount that can flow depending on the input voltage. They're also superfast (

[@sjh7132]

This is a good simple tutorial. You might have mentioned that it might not be good to turn the transistor half on because it could overheat.

[@wilfredmulenga5558]

best tutorial on mosfet transistors that I could possibly find

[@emactan]

Good mosfet intro! Just mind that drain current and the on resistance of the transistor. Don't want to fry the device do we? And speaking of frying, rid yourself of static electricity before handling them. Wrap them in aluminum foil when storing I used to employ S901x npn/pnp as my all around standard switching transistors. They're cheap. But when I discovered the 2N7000 I've been using them anywhere I can. Saves me the trouble of putting in and computing for gate current limiting resistor

[@creativejunior7060]

Nice, because of you i just repair my old and rusty angle grinder with brown armature. And now it really works good. Thanks

[@Afrotechmods]

Yeah it helps to 'dumb it down' in your head. Just think that current flows from positive to negative. Up to down. Don't visualize electrons moving - to +, instead visualize streams of water moving + to -. Shifting your mindset to the water analogy helps separate the two conventions.

[@jbrenes]

Best Transistor explanation out there, Great JOB!

[@cecilomar]

Getting a refresher on mosfets... Went to like the video... Already liked it at some point... I wish I could like it again.

[@GeraldFrownyPants]

What you need is a small piece of plastic that covers the camera just big enough to stop the rain coming down. Wind blown rain may still be a problem. Just make an infrared emitter array and disable the camera infrared, put the camera in a plastic case and done.

[@mikemetallia]

Thank god for one normal tutorial on mosfets. And thank you.

[@CharlieTechie]

Great tutorial! Simple, Clean, to the point with a little humor.

[@Afrotechmods]

@floydiangreen That's connected to the symbol marked ground.

[@artype9550]

the most amzing electronic guru i ever known

[@Afrotechmods]

Meow

[@Paul67558]

afroman i think you have the only channel where can i can learn electronics

[@DoneFishin]

Voltage & Current are stored in Inductors and when the electric field of the Inductor collapses, the voltage tends to collapse to a negative version of itself. The diode protects the transistor from what is known as back emf (electromotive force) by limiting the voltage to the voltage at which the diode goes into conductance, which only happens when the field is reversed.

[@Afrotechmods]

Sorry, it's a convention electrical engineers use. The ground symbol in these circuits does not actually need to go to the earth ground in your house's wiring. You can basically think of the minus wire from your power supply/battery being the same as ground. The ground wire should definitely not go to the positive terminal though! That would be a short circuit!

[@mkayeka]

You are making electronics way easier and much fun. Thank you very much Sir.