MOSFET Transconductance and MOSFET Small Signal Model Explained

[@ALLABOUTELECTRONICS]

Timestamps: 0:00 Introduction 0:37 What is Transconductance? 2:06 Different MOSFET transconductance equations 5:47 MOSFET Small-Signal Model

[@anoopcc2361]

Sir I wanted to thank you for your videos I got placed in my core job at MaxLinear for higher package, especially your practical explanation of circuits was helpful for me in interviews ❤️

[@radhakrishnatalks7499]

What is amount ofpackage anna

[@ritabanbiswas4489]

Congratulations! How did you apply there?

[@PRACTICALPARTHA]

Congrats brother

[@honeypaaturi9979]

Thank you so much, just can't show enough gratitude through words. You're the real teacher.....☺️🤗 Understanding a concept thoroughly gives such satisfaction to student that we just can't express it enough. 🙏🏻🙏🏻🙏🏻

[@finalinvention]

Thank you for valuable lecture. One question. Why VDD is grounded? Shouldn't mosfet be saturation mode which requires large Vds?

[@ALLABOUTELECTRONICS]

This is small signal analysis. So, for that, all the DC voltage sources in the circuit has been assumed as zero. That's why VDD is grounded.

[@killermitians7640]

At 11.20 is the current flows in clockwise direction?

[@ALLABOUTELECTRONICS]

No, its flowing in the anti-clockwise direction.

[@killermitians7640]

@@ALLABOUTELECTRONICS but i can't understand it sir ....can u explain it for me ?

[@ALLABOUTELECTRONICS]

@@killermitians7640 The dependent current source is connected between drain and source. (Downward direction) On the left, gate to source terminal acts as an open circuit. So, there is only one way that current can flow. Through drain resistor. And to satisfy KCL, it will flow from bottom to top through drain resistor. Or in other words, in the loop, it is flowing in the anti-clockwise direction. I hope it will clear your doubt.

[@killermitians7640]

@@ALLABOUTELECTRONICS Thank you so much sir ....sir a humble request do make videos on MOSFET biasing as soon as possible as we are having our exams on January.....btw thank you once again sir

[@ALLABOUTELECTRONICS]

@@killermitians7640 I have already made videos on it. Please check the JFET and MOSFET playlist. You will get it. Here is the link: kzbin.info/aero/PLwjK_iyK4LLC-tRT_Uml3T-ifdcmuykjV

[@MuntahaRahman-m9d]

why do we only do small signal analysis in saturation region?

[@ALLABOUTELECTRONICS]

Because in the saturation region, MOSFET acts as a voltage controlled current source. And in that region, it can be used as an amplifier. Using the small signal analysis, it possible to find the relevant characteristics of the amplifier. (Gain, input and output impedance etc)

[@user-ge8hj9br6w]

can you teach to find net transconductance and output resistance of mosfet combo circuits

[@ALLABOUTELECTRONICS]

It has been already covered in the cascode amplifier video.

[@user-ge8hj9br6w]

@@ALLABOUTELECTRONICS oh yes, thank you

[@bestofbest8213]

kinly make play list , it is very hard find specific vedios

[@ALLABOUTELECTRONICS]

Please check JFET and MOSFET playlist on the playlist page. You will find all related videos there.

[@zulfiqarali2563]

اردو یا ہندی یا براہوٸ میں لیکچر دو سر جی سرجی انگریزی میں کیا بتا رہے ہو

[@opposites-369]

Finnaly at least Hindi with English pronounce & English subtitle, thx bro 🙏🏻👍🏻, I really learn from you, uh.. I hate Hindi, urdu, bangla, tamil with no translation or English subtitle 😠😡🤬

[@hrkalita159]

Did anyone ask you?

[@薇季芬]

0:39-0:46 to use the mosfet as a amplifier, it should be operated in the saturation region 如果要用mosfet當作放大器，那麼應該要保持在飽和區 0:46-0:54 because the drain current iD is a function of voltage VGS 因為電流iD是一個電壓的函數 0:54-1:00 but if you see the relationship between drain current and the voltage VGS,you will find the relationship is not linear.但如果你觀察drain current iD和電壓VGS的關係，你會發現這個關係不是線性的 1:40-1:55 it is defined that the transcinductance of the mosfet. ths transconductance is equal to the change in the drain current divided by the change in the voltage VGS 定義一個東西叫做conductance=drain current iD的變化量 除於 電壓VGS的變化量 2:01-2:06 從圖形上來看consductance就是operating point的斜率 2:26-3:02 微積分內容 3:11-3:22 from this expression,you can see.The transconductance is proportional to VGS minus Vt.從這條式子可以發現，當使用同一個mosfet時（意即mosfet參數不變），transconductance 和 (VGS - Vt) 成正比 4:38-5:41 最精簡的方式表示gm

[@iamavolk]

Immense respect for you, sir, and many thanks! One of the best educators on KZbin.

[@passion_is_]

Sir we are waiting for your next video plz post the next topic as soon as possible

[@sanderbank2058]

Thnx you are really good at explaining these things

[@michaelpogrebitskiy6122]

I have my microelectronics final exam in 4 and a half hours, and the small signal model always confused me. Thank you for this very understandable explanation!

[@exaltant2464]

why am i giving fee to college?

[@heregulmithal7063]

Wonderful presentation.

[@प्रणव_गुप्ता]

Sir what is general value of the small signal Vi in practical experiments??

[@ALLABOUTELECTRONICS]

Up to few mV signal.

[@teresafaasolo144]

Is this process the same for when we calculate for the transconductance for a Mosfet in a triode region?

[@camilotello3296]

Sir, I'm extremely happy I came across your video, this explained a lot and was really insightful. Thank you so much!!!

[@Lwyte17]

Dude, awesome! Thanks for making these great videos.

[@lakshmipriyanka4490]

Thank you so much sir

[@piyush-hp9pz]

thanky you sir

[@ececse]

thankyou sir.

[@user23xx76]

thank you ^^

[@supoyu6893]

Really help!

[@neilharris478]

At the very end of the video, the polarity of Vo being positive on upper rail and negative on lower rail is as many textbooks show it. But current flows UPWARD through the resistor from the lower rail, making the resistor more positive in its lower half. HOWEVER, you explained that vo = -gmViRd (the minus sign helps clear this up!) Thank you!

[@anveshreddy1245]

Can you explain large signal model of mosfet

[@bipulkumarsingh554]

can u make video on switch capacitor pls

[@venkateshwaran292]

Very helpful video. Clear and to the point explanation.

[@theminertom11551]

Very clear explanation!

[@guhbnu]

excelent explanation!!!!!!

[@jivey5123]

Hard to listen to.

[@dr.vandanakhanna8813]

Very nicely explained. Great!

[@raeafreund9242]

This is so clear thank you!!!

[@akshatsharma7639]

wow amazing explanation.

[@kommsk]

Very good job bro

[@hasibuddin2437]

Thnks

[@vinaykumarkv5830]

Thanks a lot ❤

[@suryakanth5370]

Sir if vi

[@ALLABOUTELECTRONICS]

2 Vi (Vdc - Vt) will be small but Vi^2 will be even smaller. And hence Vi^2 term can be neglected. For example, let's say Vi = 10^-4 V and Vdc - Vt is 1 V. So, 2 Vi (Vdc - Vt) is 2 x 10^-4, while Vi^2 = 10^-8. So, if you compare both terms then Vi^2 is much much smaller and hence in comparision to other two terms it can be negleted. I hope, it will clear your doubt.

[@rohitnaidu2432]

does the current direction change based on p-type or n-type classification?

[@ALLABOUTELECTRONICS]

For p-type, the current is flowing from source to drain.

[@pavansai6338]

🤯

[@rahulkurup3351]

sir please share these notes

[@ALLABOUTELECTRONICS]

The notes are available on the website. Please check www.allaboutelectronics.org

[@harshbardhanon4901]

sir why Vgs=Vdc+vi

[@ALLABOUTELECTRONICS]

The voltage Vgs is the superposition of the DC voltage (which is appearing between the gate and source terminal) and the AC input signal (which is also applied between the gate and source terminal). The Vdc is the required biasing voltage, while Vi is the AC input signal which we want to amplify. I hope, it will clear your doubt.