MOSFETs and How to Use Them | AddOhms #11
HTML-код
- Опубликовано: 6 фев 2025
- MOSFETs are the most common transistors used today.
Support on Patreon: / baldengineer
They are switches that can be used an Arduino, BeagleBone, or Raspberry Pi. This is part 2 of a 2 part series, which covers MOSFETs. (Part 1 Covered BJTs).
When it comes down to it, MOSFETs are pretty complicated devices. This video will cover the basics of what you need to use them in your circuit, including calculating if you need a heat sink or not.
Learn what they are and how to use them.
Part 1 (BJTs):
• BJTs as Transistor Swi...
Show Notes:
www.addohms.com...
Follow us on twitter: @addohms
#mosfet #transistor #
When looking at a datasheet, do NOT use the value of Vgs in the section "Absolute Max." This section is for conditions that will damage the MOSFET. More information here: discuss.addohms.com/t/what-does-absolute-max-mean/72
Nikša No additional components are required for basic switching. For high speed one would likely need a higher drive current (because of the gate capacitance) than can be provided by a signal generator and physically adjacent rather than at the end of a cable. Just ensure that the generator swing goes close to zero to ensure 'off' and for fullest conduction the drive voltage should approach the maximum allowed on the spec sheet.
But do you actually need a BIMOSFET? Plain MOSFETs are much more readily available and cheaper. Old PC motherboards are a good source. If you do need the enhanced high voltage capacity of a BIMOSFET it might not be particularly wise to embark upon such experiments until you have gained more experience because it can be dangerous and expensive. Have fun though.
BTW, BIMOSFETs are just IGBTs, the additional name is just marketing. And IGBT is a silly name anyway 'GIT' (gate insulated transistor) would have been far better, that's what we call them in the lab.
Traslate to pt-BR, please..
AddOhms a
One question, we are working with a 2n7000 n channel transistor and in the drain caracteristics grafic states that the id max its reach at Vgs=10v with 1.5ma aprox. why its this, isnt it supose to be at Vgs=0v idss?
I look at the Vgs and even the Vbe on BJT as what will kill it, and have put an LED on that location between base to emitter or gate to source to prevent the damage, as even a BJT can have too high of a voltage when there is not enough load on the collector when in darlington configuration. Best designs are ones that take into account what might happen to cause failure, then if something unusual happens it does not die on you.
finally... someone explained how to select the mosfet in practice... in university they are all about calculating amplification, working of a mosfet in molecular level, etc. but they won't tell simple things like these, which are super important when using and selecting the transistor in practice. Thank you, sir!
I agree, I just knew they were voltage controlled -_- This guy taught me so much in 7 minutes, I really liked the datasheet part (at school they just throw questions and say to use the datasheet, but not explain what to look for or determine if a heat sink would be required)
........I remember those type of textbooks.. It's important to have a play with the components to get familiarized. I'm surprised how many people don't know a simple set up with a p and n channel jfet that results in a tunnel diode effect but when I first came across this simple circuit I just had to try it out and it produces excellent sine waves according to my hearing perception.
@dylans voice Which is why some companies are moving away from schools. Had an interview taking 3 hours of an online quiz, had questions from basic programming to PCB design. They had open internet and said go for it. We will contact you if you are selected after it was completed.
Overall, the best interview I could say that I had, I also believe they had 7-8 other candidates taking the test, we were all spaced like 15 minutes apart to have the 1 on 1 personal questions.
I failed Electronics as a subject and hated it for its Transfer Functions, but I could build any circuit I chose to. Damn lecturer was as boring as mud
@dylans voice yup cheaper too 💀
Excellent! Finally someone covered the stuff one actually needs to know for their projects. I'm trying to buy a MOSFET, not design one.
I'm making t-shirts that say "I'm trying to buy a MOSFET, not design one." That expresses my - an many people's - frustrations perfectly, and why I also very much appreciate this video even 8 years later!
😂
This is, BY FAR, the most comprehensive and accurate tutorial for MOSFETs on RUclips.
"Most accurate..." except for the part where I draw a depletion mode symbol while explicitly stating it is an enhancement mode symbol. ;)
Hi James. This Channel is one of the BEST anyone can find in RUclips.
I really like your videos. My reasons:
1) Your diction is great, extremely clear, well articulated.
2) You have music ONLY in a few spots, which I consider that is perfect. I hate those tutorials when it’s almost impossible hear what the person is saying.
3) You visual and graphics material are of the super highest quality.
4) Once in a while a joke is perfect, as an “ice breaker”.
5) You have a great respect for your audience.
A+++ 👍 I subscribed to your Channel & Turned On the notifications.
Congratulations!
My uncle is an Electrical Engineer. I have asked him many times about mosfets as I have been watching him working on circuits since my childhood. But every time his lectures just flew over my head. Then I searched youtube and got my answer.
I have years watching electronic videos on youtube, and i can tell maybe 5 are the channels that are actually worth to watch, this is one of them..great job mate
This is my favorite AddOhms video. The viewer KNOWS they need a MOSFET and you show them how to use the data sheet to select one. The review is a nice touch too.
I wasted about 1h in googling some informations abour BJTs and/or MOSFETs. And now after more than the half of the time, I got what I need. Thanks man! :-)
I love it how you broke down the complex systems into easy to understand simplicity. That, and the random humor helps keep things interesting.
My professor talked about this but with you assistance this now makes clear sense.
I really do like your approach to teaching this concept.
Very easy to understand and the anecdote at the beginning was a good way to diffuse any tension when learning new concepts.
I agree!!! Sometimes I wish there was a pause button to push to slow down professors, or a please make this clear button - no such luck!!
Great Video - after 40 years as an EE I now understand MOSFETs a whole lot better.
I've been trying to increase my limited Electrical knowledge, and your videos are some of the most informative and easily understood. The fact that you back them up with fact/cheat sheets on your website is really a nice touch. Look forward to some more videos from you in the future, they've done me a lot of good. Thanks
In just a couple minutes, you have explained clearly the selection and the application of MosFET. Thank you!
Thank you for making these videos because you don't just throw equations at us but you explain how fets mechanically works and then use the V,R I's in equations but they're within the context of your tutorials.
this is a great video. really enjoyed how you not only explained the functionality of MOSFETs but how to actually use them in a real-world application. thats something i wasn't taught when i was in school (not sure why though).
Sorry I don't understand?
School is the slow way to learn :/
youre absolutely right, the truly deal is out there, were's the real troubles are,
I took eet in college many years ago. This 7.45 minute video is worth 2 hours of class time as far as I am concerned. The classes I took were not bad, it is just that there was an extreme reluctance to get into anything practical.
Well using them in a small project in class is more difficult plus some also has sensitivity to ESD which isn't good for a class that may not use precautions
30 seconds in and I've seen an engineer with an efficient hairstyle, information on transistors and MOSFETs and seen an intro.. subbed!
Now THIS is how an instructional video SHOULD be! Awesome work, have subscribed. You taught me more in a couple of minutes than all the so called forum experts and their arguing and sniping at each other! Just THANK YOU!!!
When you started talking about mosses I just rolled with it. really shows how easily zoned out I can be :P
I really appreciate the moss joke. I'm interpreting it as a reference to how so many of these videos or articles go straight down into the weeds of stuff you really don't seem to need to know to get started learning how to use these things.
Thanks, but you put more thought into it than I did. I just wanted to point out the videos are scripted. People are often ask: "how do I make videos like yours?!" I always say: "start by writing a script."
Thank you for making this video so much, good sir! I wish that my radio lab instructor could explain all the concepts as clearly as you did in less than 10 minutes. You got a real gift.
Probably one of the best tutorial on MOSFETs on the Internet. Thanks for sharing...
Thank you. While I knew the basics in general, your video here showed me what I was getting wrong and what I was getting right. Now that I know how to interpret a datasheet *correctly* and what to look for, I can make better decisions for designs.
That's all I am looking for is plain spoken direct explanations.
Thx, finally a beginner oriented and well explained tutorial.
Great Vid with no annoying background music. Subscribed
...my very first YT comment.... You have the most captivating presentation style and use of transitions and tricks EVER!! ciao, lm
Hey man, thanks for the videos! They're not only clear, but the production is pretty good. Keep 'em coming, they're much appreciated.
I like your teaching style. It's easily understandable with no silliness. Thank you
Your MOSFET guide/worksheet is great. So are your videos. The guide/worksheet has helped me immensely with an IRF540.
I had no access to videos like these nor invested teachers back when I took electronics in high school. Seeing it taught like this makes me realize how different my education could have been... how different I could have been.
There should be a government subsidy to pay RUclipsrs for producing educational content that can replace classroom lectures.
I was so impressed I subscribed before the video ended. Keep up the good work.
Same here, I agree.
MOSFETs were a godsend to me when I was transitioning from vacuum tube circuits to solid state. Because they are both voltage driven, it was fairly easy to adapt the designs from one to the other. That gave me some breathing space while I got my head wrapped around current driven BJTs.
I feel a rudely impulse to ask what you were building
When you started explaining about moss i really thought there was a deeper connection between Mosfets and moss and started having all sorts of imagination about how it could be related....
A lot of videos on MOSFETs goes into too much details and ended up confusing. But this is perfect, just enough of what I need to know. Thanks!
Man I love this stuff. I should have become an electrical engineer, I find all this so interesting.
What did you do instead?
Same here , I choose IT instead.
I love that you make the connections between the datasheet and the behaviour! So great!
Great explanation about heat. Thanks, it is often overlooked because it is confusing, but your explanation was superb. Thanks!
Just don't forget that the ambient temperature won't always be 25°C. If the installation is some cupboard next to a south-facing window, you can bet that it'll get up to 45 in there and let the smoke out.
Just ran across your channel and I am so glad. Love your training material and presentation. As an instructor, I may a little fussier about videos, yours are great. Never seen whiteboard style like this. I also learned more about what I didn't know about MOSFETs in less than 10 minutes. I am a new subscriber. Keep broadcasting!!
Very well done tutorial, I am pleased it was suggested by youtube. subscribed.
MOSFET aka Metal Oxide Smoke & Fire Emitting Transistor 20 years ago my nickname was 1 leg MOSFET ... because the other two burned off. Let's just say some of my motor controller designs suffered from insufficient heat dissipation and or catastrophic back EMF issues. I always said "fire is the other way to learn".
You know you are into electrics when you have a favorite type of transistor.
Excellent. Succinct and to the point, and gives you a logical approach to choosing a MOSFET that meets your switch application requirements. If only the manufacturers and/or distributors would put a tool on their web pages to help you make a selection using this approach!
Good video, you have another subscriber. Keep up the good work.
I know it doesn't really come into play until one uses MOSFET's in fast switching applications, but one has to remember, that the Gate has tiny bit of "capacitance". The Gate has certain amount of charge that needs to be filled in order for it to change the Rds. And this amount is dependent on the size of the gate, thus high voltage and current MOSFET's have bigger gate charge.
It's measured in coulombs, so if you want to switch the MOSFET on very fast to minimize the time that it's in linear region (thus minimizing the losses and heat) you want to have quite significant current delivery to the gate when switching on and you also want to discharge the gate as fast as possible when going to the other direction :)
Because of this, it's not advisable to use very large resistor in series with the Gate, but also it's not advisable to plug MOSFET to a microcontroller pin without it or you can break the IO pin.
Thus there are driver IC's available for this application :)
This is definitely something I want to cover in more detail in the future. But that's why I snuck the resistor into the drawing for this videol
I myself learned about it when building a LED cube and trying to figure out how to switch different layers on and off fast enough to minimize the "afterglow" when multiplexing :)
Great video. You put in lot of effort into doing this and will greatly benefit lot of beginners. Kudos.
Thanks alot! English is not my mother tongue, but its much more clearer then in school learned by a teacher :)
Love the hydrgen peroxide joke in the intro.
Here another one:
*There are only 10 kinds of people, those that understand binary and those that don't.*
Actually, it's 11, those that understand binary, those that don't and those that know tristate
A really cool feature of FETs is that many of the enhancement mode type can be triggered and stay triggered with nothing connected to the gate! That’s also it’s downfall as a FET in an SMPS can stay triggered and pop if a suitable gate resister isn’t used to stabilize off time.
Nice video. Love the 'autorouter' shirt. ^_^
At 0:28 The other says "I'll get H2O" too ... the second guy might die, but at least he'll be disinfected by H peroxide. ;)
I love the way you present, to the point well done. Good sound quality too for us old guys. I took electronics for 3 years but still need a refresher now and then. Thanks.
Thanks.
Wow, what a fantastic video. Great stuff, very helpful
Holy moly, great video my man! Very detailed and I appreciate that you have even more information linked to your own website! You've most definitely earned my subscription! Thank you!
Great video, very well produced! :)
This is the best transistor explanation I have heard to date.
I think I found my "RUclips channel". Thanks, sir.
This should be the only video found for the term "mosfet usage". Thank you!
We are waiting for a lesson about IGBT!
Thank you so much for the explanation of details of which up until now eluded me due to the language used when studying previously. Now everything just clicked! Saved your video for future reference, just so easy to understand. Many thanks, wish you all the best.
Yeah, liked the H2O2 joke! The old ones are always the best ones!
amazing video
taught me more about this wonderful invention in 6 mins then professors have over the past 4 years...
i agree
I still think those depletion mode mosfets each contain a tiny little vacuum tube
Awesome simple explanation/app note. Quick, fast, cheat-sheet style. love it!
Absolutely professional Video! Thank you!
Loved the simplicity and ease of explanation. I was struggling to use a P-Mosfet with 24V rail. and Vgs>20V. read in comments below, an advice to use a voltage divider. Thanks....
You misread the data sheet. That is the maximum Vgs. Not the threshold.
You may also want to read this: www.baldengineer.com/p-channel-mosfet-tutorial-with-only-positive-voltages.html
Great video. However, almost nobody talks about the necessity of using a resistor between the gate and the ground to sink the current trapped in the gate and for turning the mosfet off properly in any mosfet video on youtube...
Excellent point. It's something I already planned to cover in the future. However, it is exactly why I at at least included in the schematic, to hopefully prompt the question "why is it there?"
This is not a hidden secret of electronics. However, I have learnt that the hard way after hours of google search and experimenting. And sometimes such small details can be really demotivating for an hobbyist or a beginner... It would be good, if you can cover this in the next mosfet video.
Wow, thanks so much! Was wondering what I was doing wrong. Any idea what type of resistor is needed to ground (I put in a 2k which seemed to work fine). Also, I assume there should also be a small resistor from the positive voltage to the gate as drawn.
Thanks
You’re welcome and thank you.
Great video, subscribed!
same!
Me too.
Hello.
Hey!
You explanations are excellent and very easy to understand.
Brilliant! Very nicely illustrated.
By the way, do you perhaps know how to dimension the external gate resistance to a mosfet driver? I'm having a really hard time finding anything about this.
Sveinn Grétarsson why are you trying to determine that?
It's fine, I finally found a decent article covering this. The reason is that I am currently working on a hydraulic solenoid valve driver circuit which used a 200V mosfet as a switch, and used a mosfet driver (LM5112MY) as gate driver. The applicaiton note of the driver stated that an external gate resistance should be used, but never mentioned any guidelines as to how it should be determined.
It is ofcourse just an RC circuit, of which you determine the resistance to get a predefined time constant. Silly me. :)
Great video! Gets right into practical application to show you how to select the device that will work for your circuit. Love it! Please keep this kind of content up!
Regarding the 2 guys in the bar ordering H2O, the second guy dies because he ordered Hydrogen Peroxide H2O2(too).
I had to read that 3 times to get it. is that bad ?
kind of!!
voltixD thanks!!
If he didn't, at least he got a nice diarrhea.
voltixD . Hahahahaha
I like how easy your videos are to understand but they are so short that you don´t cover a topic fully. Even if you were to cover them sequentially which you don´t by the time the next video comes out the person/learners have already forgotten what was covered in the last video.
0:28 I get it, the second man drank hydrogen peroxide.
This is video is gold, I feel lucky for finding you channel. Thanks for the excellent explanation 😀
Very nice and unusual presentation, clear script too.
Liked the joke but I now need to find out what chemical H2O2 is.
Your picture of the Enhancement MOSFET @2:17 is blured and looks more like a Depletion mode type. Could cause confusion.....
Sub'd...........
+Michael Hawthorne
Aahh the wonders of Google.... H2O2.... Hydrogen Peroxide.
+Michael Hawthorne Yeah, I drew it wrong.
H2O2 his hydrogen peroxide
the chemical which caused the disaster resulting in the sinking of submarine Kursk
maybe consider putting a note in the description?
I doubt it! Western Media Story. My guess is that those rumors about an accident (collision) between Trident US Navy submarine and Kursk are more true than not. These collisions happen all the time, they are just not reported about. Often in Black Sea. Often between ships, less likely submarines. I am fine with these collisions being kept in semi-secret mode. There is one story for the public, another for inner circle. Sadly, this makes sense as most people are no longer capable of critical thinking. "Democracy is based upon the conviction that there are extraordinary possibilities in ordinary people."
- Harry Emerson Fosdick
The best video on microelectronics I have seen so far.
dont forget the Boba FETs
Great video, showing the datasheets is awesome as it's the way we would need to look for them too. Great video.
Moss...I lol'd!
LOL
._.
I really enjoy the video and learned a lot in little time. I wish most of the tutorials were like this one. I would say people empowering people !!! THANKS ⭐⭐⭐⭐⭐
Fantastic video- first thing I found which actually helped me to put the MOSFET into practice myself. Thank you so much
Best video about mosfets on all of youtube.
Thank you James 🙏
You just explained what 5 of my university professors couldn't. Thank you. At last
Hi James, i am from Brazil and would thank you for this videos, i'm loving your channel.
Tem que falar que é do Brasil, né? Kkk
Sim, pra que ele saiba que o trabalho dele está sendo curtido pelo resto do mundo.
Great video. I wonder how you present a technical thing in so much interesting way. Very clear and understandable. Thank you very much!
+S W Lee With a lot of practice.
Nice explanation! Not too much information unlike other channels! Great work!
Absolutely wonderful video man. Would love to see this education approach on how to implement high and low side switches using MOSFETS
Excellent clear concise and not oversimplified
Con mi poco inglés aprendí más con este video que en las clases de mi escuela. You get my like!
+Robby De nada
Great video. If I am correct, MOSFETS are also High Impedance devices with very low noise factor.
Excellent teaching skills there James, a real credit to you. I've subscribed. Great video look forward to more of them - you've so much to contribute with your clear style. Many thanks from across in the UK.
Concise, a classic I have to re-watch every so often.
Just awesome, so short, so compact, and yet "all" you need to know. Thank you very much!
This was a really good video, even if it's several years old by now. I'm just learning about MOSFETs and I was unsure on how to calculate the heat-dissipation thing, but you made it pretty damn easy and clear. I also quite enjoy your style of presentation here. I suppose I should check out the rest of your videos for more good stuff!
Just found your channel. Even though I'm not an english native, this video helped me a lot to get into this. You got my sub.
your presentation impressed me to proceed with mosfets. awaiting further about mosfet application.
Great video and helped me plan for a small project I am about to do with my son. I am learning so this video helped me to plan the h-bridges we need to build.
One of the best videos on mosfets, thank you!
Awesome.This is the biggest crossover from IoT to high power application.
Really well explained and easy to understand. Thanks.