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Operational Amplifiers (OpAmps) and Comparators

Operational Amplifiers (OpAmps) and Comparators. Signal Conditioning, Buffering, Etc. 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. Operational Amplifier.

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Operational Amplifiers (OpAmps) and Comparators

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

  2. 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. Operational Amplifier

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

  5. 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. The Golden Rules: Apply only when the op-amp is operated:

  7. Vin True Source Resistance Perceived Vin

  8. What Happens to the output if we tie the two inputs together?

  9. Input Offset Voltage

  10. Input Offset Voltage Specifications

  11. Effects of Input Offset Voltage

  12. Input Bias Current

  13. Input Bias Current Specifications

  14. Can We Correct for Input Bias Current?

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

  16. Does that fix the bias current problem?

  17. Output Voltage Limitations

  18. Output Voltage Specifications

  19. The Importance of Test Conditions “RL = 2kW”

  20. Specifications that you shouldn’t use:

  21. Specifications that you shouldn’t use:

  22. What is the minimum values for R1 & R2 if Vout is driving a 10kW load and we want to achieve a 3.3V output? LM324

  23. Frequency Effects

  24. Large Signal Frequency Response

  25. Slew Rate Effects

  26. Extreme Slew Rate Effects

  27. A Comparison of Some Op-Amps

  28. Questions?

  29. What is This?

  30. How might you use it?

  31. Without With

  32. How do you achieve it?

  33. Eliminating the separate VREF

  34. What’s going on?

  35. Inverting Comparator Design Procedure Trip point at 1.5V, 0.25V Hysterisis

  36. The Non-Inverting configuration:

  37. How does this circuit Behave? R1=3kW, R2=R3=1KWVin sweeps from 0-5V

  38. How about this one? Vin = 5 to -5V Sin What are the thresholds?

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