# Finding Thevenin Equivalent Circuit

1. Feb 7, 2013

### Lancelot59

I'm given the circuit in the attached image (I just quickly re-created the circuit in LTSpice to save on drawing time).

In the first part of the question I managed to find the S domain transfer function without any issue. I found the transfer function as some function of the resistors, capacitors, and S.

Now however I need to find the thevenin equivalent at the point V2(t), and I'm not quite sure how to get started with this working in the S domain.

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2. Feb 7, 2013

3. Feb 7, 2013

### Lancelot59

Oops, I left a connection in by accident. Ignore the short. Finding the impedances was easy enough, and like I said I found the transfer function.

A thought occurred to me. Isn't this going to wind up being the equivalent series impedance, in series with a voltage source that is the the transfer function?

4. Feb 7, 2013

### Simon Bridge

You can find $V_{AB}$ - a bit more care is needed for the input impedance.
Just go through the normal steps for finding the equivalent circuit. You should be able to satisfy yourself about the validity if you keep in mind what the various bits of math mean.