# Find the transfer function

## Homework Statement

find the transfer function H(s)
[PLAIN]http://img192.imageshack.us/img192/4204/asdwoe.jpg [Broken]

## Homework Equations

H(s) = Vout/Vin
done in the frequency domain so: C1 and C2 turns into 1/sC
where C1 = C2 = .1F
and R1 = R2 = 20

## The Attempt at a Solution

to find the transfer function, i have to apply an impulse source. therefore, Vin is just 1V.
my attempt at this by using node voltage method:
(Vx is the node that connects R1, R2, and C2)

(Vx -1)/20 + Vx/(10/s) + (Vx - Vout)/20 = 0

i am stuck with two unknowns and 1 equation. :[

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bump, anyone?

The Electrician
Gold Member

## Homework Statement

find the transfer function H(s)
[PLAIN]http://img192.imageshack.us/img192/4204/asdwoe.jpg [Broken]

## Homework Equations

H(s) = Vout/Vin
done in the frequency domain so: C1 and C2 turns into 1/sC
where C1 = C2 = .1F
and R1 = R2 = 20

## The Attempt at a Solution

to find the transfer function, i have to apply an impulse source. therefore, Vin is just 1V.
my attempt at this by using node voltage method:
(Vx is the node that connects R1, R2, and C2)

(Vx -1)/20 + Vx/(10/s) + (Vx - Vout)/20 = 0

i am stuck with two unknowns and 1 equation. :[
Write another equation, then you'll have 2 equations and 2 unknowns. I would write one at the output node.

Last edited by a moderator:
CEL
The difference between the voltages of the output and input nodes is the voltage across C1 and also the sum of the voltages across R1 and R2.