1. CMPE 118 MECHATRONICS Operational Amplifiers (OpAmps) and Comparators Signal Conditioning, Buffering, Etc.

2. CMPE 118 MECHATRONICS Operational Amplifier Difference Amplifier V + > V - then the output is driven in the Positive direction V - > V + then the output is driven in the Negative direction

3. CMPE 118 MECHATRONICS Operational Amplifier

4. CMPE 118 MECHATRONICS How do we use Op-Amps then? Negative Feedback

5. CMPE 118 MECHATRONICS The Golden Rules: Apply only when the op-amp is operated: Within its listed specifications In Negative Feedback 1) The Inputs Draw no Current 2) The inverting and Non-inverting inputs remain at the same voltage

6. CMPE 118 MECHATRONICS The Golden Rules: Apply only when the op-amp is operated:

7. CMPE 118 MECHATRONICS

12. V in Source Resistance True Perceived V in

13. CMPE 118 MECHATRONICS What Happens to the output if we tie the two inputs together?

14. CMPE 118 MECHATRONICS Input Offset Voltage

15. CMPE 118 MECHATRONICS Input Offset Voltage Specifications

16. CMPE 118 MECHATRONICS Effects of Input Offset Voltage

17. CMPE 118 MECHATRONICS Input Bias Current

18. CMPE 118 MECHATRONICS Input Bias Current Specifications

19. CMPE 118 MECHATRONICS Can We Correct for Input Bias Current?

20. CMPE 118 MECHATRONICS Does that fix the bias current problem? Not Quite The two bias currents are not exactly equal This is the Input Offset Current

21. CMPE 118 MECHATRONICS Does that fix the bias current problem?

22. CMPE 118 MECHATRONICS Output Voltage Limitations

23. CMPE 118 MECHATRONICS Output Voltage Specifications

24. CMPE 118 MECHATRONICS The Importance of Test Conditions “R L = 2k  ”

25. CMPE 118 MECHATRONICS Specifications that you shouldn’t use:

26. CMPE 118 MECHATRONICS Specifications that you shouldn’t use:

27. CMPE 118 MECHATRONICS What is the minimum values for R1 & R 2 if V out is driving a 10k  load and we want to achieve a 3.3V output? LM324

28. CMPE 118 MECHATRONICS Frequency Effects

29. CMPE 118 MECHATRONICS Large Signal Frequency Response

30. CMPE 118 MECHATRONICS Slew Rate Effects

31. CMPE 118 MECHATRONICS Extreme Slew Rate Effects

32. CMPE 118 MECHATRONICS A Comparison of Some Op-Amps

33. CMPE 118 MECHATRONICS Questions?

34. CMPE 118 MECHATRONICS What is This?

35. CMPE 118 MECHATRONICS How might you use it?

36. CMPE 118 MECHATRONICS WithoutWith

37. CMPE 118 MECHATRONICS How do you achieve it?

38. CMPE 118 MECHATRONICS Eliminating the separate V REF

39. CMPE 118 MECHATRONICS What’s going on?

40. CMPE 118 MECHATRONICS Inverting Comparator Design Procedure Trip point at 1.5V, 0.25V Hysterisis

41. CMPE 118 MECHATRONICS The Non-Inverting configuration:

42. CMPE 118 MECHATRONICS How does this circuit Behave? R 1 =3k , R 2 =R 3 =1K  V in sweeps from 0-5V

43. CMPE 118 MECHATRONICS How about this one? V in = 5 to -5V Sin What are the thresholds?