# Homework Help: RC Transfer function

1. Apr 4, 2015

### alexmath

1. The problem statement, all variables and given/known data
R = C = 1;

2. Relevant equations

G(S) = 1/(s+1)

3. The attempt at a solution

Suppose R = C = 1 then the transfer function from the input voltage to the voltage across the capacitor is 1/ (s+1). So Vc(S) / V(S) = 1/(s+1). Getting back to time-domain: Vc(t) = V(t) * e^-t. What's wrong here? It should have been V(t) ( 1 - e^-t ). Thank you!

2. Apr 4, 2015

### Svein

How you connect R and C, where do you connect the input and where is the output? As it stands, the question is impossible to answer.

3. Apr 4, 2015

4. Apr 4, 2015

### Staff: Mentor

What's your V(t)? Suppose that the transfer function is U(s) = 1/(s + 1). You need to deal with V(s)*U(s) if you expect to find the time domain response Vc(t) via Vc(s) = V(s)*U(s).

It looks like you were looking for the time domain response of the circuit to a step function: V(t) = V*u(t).

5. Apr 4, 2015

Thank you!