Why do we call them lay terms

Explain in layman terms the Vgs and Vgs (th) of MOSFETs

Vgs is the gate to the source voltage.

In the data sheet you will find an absolute term Vgss. This is the maximum voltage that can be applied between the gate and the source. In addition, there is a risk that the mosfet will be damaged.

An N-channel MOSFET is essentially a P-type, which is arranged between two N-type regions.

Party time.

You throw a party and invite all electrons in the neighborhood to participate. So you send "PARTY AT MA HOUZE YOLO #SWAG!". That is, you are applying a positive voltage on the gate with respect to the source. Given that your neighbors are some distance away (next door), your broadcast is not loud enough (you are at Vgs (th)). Once you shout your invitation loud enough (i.e. have Vgs at Vgs (th)), your neighbors next door are listening and come celebrate with you.

Vgs (th) is the voltage at which the mosfet channel begins to conduct. At this voltage, a positive voltage, an electric field is created that attracts electrons (because our applied voltage is positive, i.e. positive charges on the gate). These accumulated electrons near the gate form a bridge between the source and drain (both n-type). Now you have a "continuous" type n path from source to drain.

You just dressed your neighbors so your party is kind of lame. How do you get more people? They send louder (increase the range of your electric field - increase your Vgs).

Now it's loud and then there is HOLY CRAP, A PLANE CRASHED IN OUR HOUSE, WHAT THE $ # @! IS THAT NOISE!?! We don't want to freak people out so much, so we need to know how much louder (the difference between) our call is than the minimum needed only for our immediate neighbors (Vgs (th)). This difference is referred to by a couple of different names, but the two I've heard most often are V-on (Von) or V-overdrive (Vov). This quantity (Vgs-Vth) indicates how much more potential there is between the gate and the source than the transistor needs to turn on and affects almost every other behavior of the MOSFET: Current in the triode (how many people are on) yours Party if only your neighbors can hear), current saturation (how many people are there when it's full of people), and transconductance (how much volume you need per person at the party) to name a few.

Now you have increased your Vgs to the point that you can no longer accept people on your property. You are completely full. You can broadcast your party as many times as you want, but there just isn't enough room for everyone. Your transistor is now in saturation. [Technically, there can be more people at the party: if your immediate neighbors are broadcasting the party (increasing Vds) and people are celebrating in their homes (source and drain), it will increase the number of people at the party (increase electricity). This is known as channel length modulation. However, this can only happen if your house is already full (channel length modulation only occurs when the device is in saturation).]

If you start increasing your Vgs to the point of Vgss, cops will show up and take you out. Underage drinking, drug use, etc. You are going to jail (your transistor has been broken).

Sam W.

I really loved that explanation! lmao

RoyC

@Yasindu I have declined your suggested edit. English is a strange language with a lot of different standards. Your edit was about changing this post from one standard to another. Even in the UK they struggle to decide how to use English properly. Avoid doing this for the future if it doesn't affect the readability of the post.

Rev1.0

What the fuck did I just read? :) This is what you get if you ask "Explain in layman's terms".