How to calculate gain in a circuit

[DreamSanchez]

http://imgur.com/K5nPY

a) Determine the voltage gain of the amplifier, Vout / Vin, in terms of the parameters in the given circuit.

b) Determine the overall voltage gain between the source and the output, Vout / Vsourse, in terms of the parameters in the given circuit.

Attempt at Solution:

I attempted condensing the resistors.
(Ro * Rl) / (Ro + Rl) becomes the new resistor on the right side.
[ (Rb * Rin) / (Rb + Rin) ] + Rs becomes the new resistor on the left side.

After this I am lost. Can anyone help me out here?

 

[gneill]

http://imgur.com/K5nPY

a) Determine the voltage gain of the amplifier, Vout / Vin, in terms of the parameters in the given circuit.

b) Determine the overall voltage gain between the source and the output, Vout / Vsourse, in terms of the parameters in the given circuit.

Attempt at Solution:

I attempted condensing the resistors.
(Ro * Rl) / (Ro + Rl) becomes the new resistor on the right side.
[ (Rb * Rin) / (Rb + Rin) ] + Rs becomes the new resistor on the left side.

After this I am lost. Can anyone help me out here?

Hi DreamSanchez, Welcome to Physics Forums.

For part (a), since you are to assume that Vin is a given, then surely you can find an expression for Vout? Looks like a simple voltage divider to me...

For part (b) you do essentially the same thing, only here you need to find Vin first given that Vsource is known.