#219: Back to Basics: Introduction to Field Effect Transistors JFET MOSFET

A basic introduction to the Field Effect Transistor (FET). This includes a basic description of the Junction FET (JFET) and the Metal Oxide FET (MOSFET), and also discusses N-Channel vs. P-Channel, as well as Depletion Mode and Enhancement Mode type devices. The function of the Gate, Source and Drain terminals are reviewed. The linear region and saturation region of operation of the devices is described and demonstrated. In a short video like this, it is impossible to get into depth in any application - the intent with this video is to lay the foundation of the operation of the FET and to make sense of the various terminology surrounding the different types of devices. The notes from this video can be found here:

[Langendimi]

After 6 years still the best intro to FETs on youtube, thank you!

[kitchinsync]

The value of your electronics knowledge is exceeded by your skills in communication. Years ago I rushed through a college EE absorbing everything but not truly grokking it. Now I have the leisure of enjoying the craft and your videos are just a pleasure to consume like a fine meal. There are few YouTubers with these communication skills and it would be valuable in the long term for your videos to not only be stored on this one platform. Links break and platforms die, I hope these videos will survive - for the future generations (the ones who will have to repair all the old FET technology handed down to them)

[CraigHollabaugh]

Hands down, this is the best explanation of basic FET operation that I've ever heard and I have a PhD in analog circuit design! Great great video. Made my day that this is available.

[rolandprocell]

After more than 3 years, I keep watching and rewatching this video. Brilliant!

[nz]

In 20 minutes you managed to explain what my electronics teacher taught in 2-3 months of classes. Truly great refresher video for me. Thank you.

[dave-d]

One of the best teachers on here! Listen to this guy. Lots. Thank you so much for your time. 73's

[paulanderson]

I just love your tutorials! Your drawings are so well thought out and drawn. I'm a 73 yr old mining engineer who couldn't get enough electronics in college, but we barely had transistors then. I will probably ask ignorant questions, but about much of this information I am ignorant. Thanks so much for what you do!

[whawaii]

FINALLY! A clear & comprehensive presentation on Field Effect Transistors. I've been struggling to get a foothold/foundational understanding of these for years. While I've known there is a difference between JFETs & MOSFETs, I couldn't distinguish or get clarification on the subtle nuances of the different types.

You Sir, are a modern day Forrest Mims. THANK YOU!

[isaacalejandroperezvazquez]

You explain all this stuff as master. Thank for your knowledge

[zersund]

You are really a good tutor, teacher and presenter. We can appreciate this even more now during this pandemics, since many of us teachers are having to prepare video-lectures. This may look easy to do for the one watching. One clear indication of your talent is your fluency. Your videos have little cuts, usually related to change of settings/equipment, no cuts related to your text. You make it very simple and practical, no fancy boards or "special effects".Yet the content is quite clear and objective. I have been teaching Physics at the university for many years now. I believe your channel, including the pdf index, should be set as one of our world resources, since your style (direct to the point) is very useful for kids in technical schools and engineering students. Congratulations.

[andreyselectronics]

I love that the multimeter in the thumbnail reads 4007, which is the name of a CMOS transistor array. Thank you for the video, it was very helpful!

[Kurt]

Best video on explaining FETs on YouTube. I really appreciate your pace and paper and pencil explanations coupled with a scope demo. All your "back to basics" videos are superbly done. Thanks!

[stanilastefan]

Your style of explaining electronics is black magic and you are a wizard of teaching.
Thank you for your efforts to light up our minds.

[DefekCs]

I know that this is somewhat arbitrary for most advanced people but for new guys it is very, very useful to see in what applications devices are used.
First step of learning - replicate: try to mimic ones work step-by-step, all of it.
Second - duplicate: try to make ones device without copying it, but by using ideas You got from set above.
Third - upgrade: try to make ones device better.
Forth and final: create: make Your own device!
See, telling about transistors, FETs and all the other good stuff You're telling, is like fulfilling second to forth steps...
Examples are awesome - all the measuring circuits, test circuits etc. Because they fill in gaps for fist step.
... what I am trying to say is ... more fist step! :D :D

But great job, really... thumbs up! :)

[Toutoula]

This is the most educational channel I've seen. You have an excellent way of describing and explaining every concept. I wish I had found this channel earlier, I would be a much better engineer today. Thank you and keep up the good work!

[MaestroCipher]

You are the best electronics teacher!!! I'm very happy I've found your youtube channel! Though I'm quite experienced in electronics I have a lot to learn from you.

[barryoshea]

At 67 years old I have just started trying to teach myself electronics and have found your videos informative, consise & interesting! Your description of real life applications of the various components is very useful! Thank you for your excellent presentation!

[elsf]

I learn more in your videos than I did in some classrooms. You're channel is incredible!👍😀

[rsa]

I have spent the last 30 years as an analog circuit designer. I just found your videos a few days ago. You have rekindled my interest in poking around in the lab. I love the hands-on nature of your videos. I have fallen into the trap of reading papers instead of independent verification as you do. Thanks for the inspiration. I subscribed, and am now watching your other videos. By the way, the family tree of FETs is a great way for me to remember things. Great stuff. As a side note, I too love hand written notes. I work for Caltech, and a bunch of us have fallen in love with an electronic note-taking tool called Good Notes. We use it with the Apple Pencil on iPads. Some of us teach entire classes now with the hand written notes. There's something soothing about it for both the students, and the teacher. It's great for designing circuits and not getting bogged down in a CAD package...

[williamogilvie]

Very well explained and quite thorough. It is difficult to pull the characteristics of different devices together, but you did that very well. The only thing you may have left out was a detail about the physical model of a junction FET. Just like the MOSFET, a junction FET has a capacitor across the channel because the substrate is connected to the Source. The gate has a wider geometry than what you showed; at least according to Siliconix literature. The electric field inside this capacitor causes free carriers to migrate away from the channel region near the source and drain, creating depletion regions.