1. Lecture 7: Op Amps Intro & Midterm I Review Nilsson & Riedel 5.1-5.3 ENG17 (Sec. 2): Circuits I Spring 2014 1 April 22, 2014

2. Overview Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 2

3. Usage: Strain Gauge Measure strain by measuring change in resistance Problem: hard to measure tiny resistance change 3

4. How to Measure Measure voltage across Wheatstone bridge Voltage still a small quantity …Use an Op Amp to amplify the voltage! 4 Op Amp = Operational Amplifier Indicates potential to perform math operations Indicates potential to amplify input signals

5. Overview Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 5

6. Op Amp Terminals 6

7. Terminal Voltage / Current 7 Follows the Node-Voltage Setup All currents set up as going into the “black box”

8. Overview Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 8

9. Voltage Transfer Characteristic 9 A = gain (multiplying constant) Use “negative feedback” to stay in linear region

10. Overview Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 10

11. Op Amp Circuit 11

12. Overview Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 12

13. Difficulties 13 PS. Don’t forget about units!

14. Thevenin / Norton Equivalents 14

15. Superposition 15

16. Max Power Transfer 16

17. Questions? 17

18. Extra Office Hours Tomorrow, Wednesday, 5-7pm Kemper 3101 18

19. Recap Usage Op Amp Overview Fundamental Operation Basic Op Amp Circuit Midterm Review 19