# Homework Help: Thvenin - Northon

1. Dec 27, 2011

### erezb84

Suppose i want to find the Thevinin Voltage equivalent between points a and b,
but there are dependent sources in my circuit that depend on the current between points a and b, how should i work?

Thanks!

2. Dec 27, 2011

### Staff: Mentor

Put your own fixed current source, I, at a-b and use the usual analysis methods to find the voltage V that this current source must have across it while connected to the circuit. Thevenin resistance will then be V/I. Since you now know the Thevenin resistance, the output voltage V and current I, you can work out the Thevenin voltage that sits "behind" the Thevenin resistance to produce V.

3. Dec 28, 2011

### jegues

I can't quite remember, but this approach only works if the circuit consists of only dependent sources. (i.e. not a mix of independent/dependent)

Correct?

4. Dec 28, 2011

### Staff: Mentor

I would think that it would work in all cases (superposition theorem), but I am willing to be corrected. Can you give an example where it would not work?