# Non ideal opamp

## Homework Statement

http://i62.tinypic.com/2n00efo.jpg

## The Attempt at a Solution

[/B]
I drew the circuit here:
http://i57.tinypic.com/10rmp20.jpg

Edit: Sorry for using this site for help so much, I just have midterms coming up soon and need to get practise problems solved and I don't have money for a tutor.

Last edited:

My recommendation: Start with your handwritten drawing and apply the existing basic rules for analyzing a network that contains two voltage sources: Superposition.
This procedure will lead you to the correct result.
Finally, you can check your result by setting (a) the open-loop gain to infinite, (b) the input resistance to infinite and (c) the output resistance to zero.
Then, you must arriove at a simple expression that is known from the theory of IDEAL opamp applications.

rude man
Homework Helper
Gold Member
Hint:
Redraw the circuit with input and output impedances OUTSIDE the op amp. Give the op amp itself a gain of 300,000.
If you do this right you will wind up with three nodes: vn, vo and vg plus of course the input voltage. vo is the op amp output voltage which will differ from vg since there will be a drop across the 5K output impedance.
Use standard KVL or sum of currents = 0.