# Homework Help: Equivalent Small-Signal Resistance of a MOSFET Circuit

1. Jan 3, 2012

### NHLspl09

1. The problem statement, all variables and given/known data

Derive an expression for the equivalent small-signal conductance Geq (or resistance Req).

2. Relevant equations

Geq = $\frac{i_t}{v_t}$

vt = vg

vs = 0

vd = -vt

3. The attempt at a solution

Attachment - EE HW 2

I drew the small-signal circuit, from what I gather it seems to be correct although I am a bit rusty on that. I began by using KCL at node vg and solving for Geq but I'm really unsure as to whether I've started this right. Looking at my work so far, to me, it seems to be on track for solving for Geq. If someone could just simply check my work/small-signal model over from what I have so far it would be greatly appreciated to earn some confidence on continuing my work! Thank you.

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2. Jan 5, 2012

### NHLspl09

Anyone have any insight on finding this equivalent resistance? I've been trying to use KCL but my answer continues to look even worse. Any help or insight would be greatly appreciated!