Chapter 5: Op Amps
Remember your basic tools for analyzing op amps. 1) The inverting and non-inverting inputs are at the same voltage. 2) No current enters the op amp. 3) The output of the op amp does whatever it needs to in order for conditions 1 and 2 to be met (limited only by the + and - power supply voltages which are not specified in these ideal problems). You will find that your conceptual understanding of where the current goes and its effects will be challenged and you will need to use your logic skills more than your math skills. Have fun!!
15. Show that the gain for the following ciruit is given by
Determine the gain when R = 10k, and R1, R2, and R3 are 100k 50k and 25k respectively.
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HEADS UP! Here are some valuable hints for the next problem.
- There is an errror in the problem statement in that the last resistor ( at the bottom) in the vertical chain should be 2R not just R
- You will need to use superposition and Thevenin equivalents to get this to work out - a very interesting and powerful example of why it can be handy to know these techniques.
- Here's a website that may help you understand what you need to do.
