1 More on Op Amps Discussion D12.1

2 Ideal Op Amp 1) The open-loop gain, A v, is infinite. 2) The current into the inputs are zero.

3 Ideal Op Amp with Negative Feedback Golden Rules of Op Amps: 1.The output attempts to do whatever is necessary to make the voltage difference between the inputs zero. 2.The inputs draw no current.

4 Non-inverting Amplifier Closed-loop voltage gain

5 Unity-Gain Buffer Closed-loop voltage gain Used as a "line driver" that transforms a high input impedance (resistance) to a low output impedance. Can provide substantial current gain.

6 Inverting Amplifier Current into op amp is zero

7 Question Find i 0

8 Question Find i 0

9 Differential Amplifier Current into op amp is zero

10 Differential Amplifier

11 Summing Circuit

12 Integrator

13 Active Filter

14 Active Filter What will the net gain be at  HI if you put two such filters in series?

15 Current-to-Voltage Converter

16 Photodiode Circuit At 50 mW