1. E E 2315 Lecture 08 - Introduction to Operational Amplifiers

2. Operational Amplifiers Ideal operational amplifiers are easily analyzed Assumptions for ideal operation are realistic Inexpensive commercial Op-Amps available as integrated circuits Practical applications for instrumentation, signal processing and control circuits

3.  A741 Pinout

4. Op Amp Terminals

5. Op Amp Terminal Currents

6. Op Amp Terminal Voltages

7. Equivalent Circuit

8. Assumptions for Ideal Op Amp Open loop Gain, A    v p - v n  0 Then v p - v n  0  R i   R i    i p  0 and i n  0 Gain is linear up to the saturation voltage Saturation voltage equals power supply voltage

9. Open-Loop Characteristics

10. Inverting Amplifier and V n = 0 and i n = 0. Then KCL at node n yields:

11. Saturated Mode Inverting Amplifier with +V cc = 5 V and V cc = -5V. R f = 10 k  and R g = 1 k 

12. Non-Inverting Amplifier KCL at node n: v n = v p = v g

13. Summing Amplifier (1/2)

14. Summing Amplifier (2/2)

15. Difference Amplifier (1/3) KCL @ n:

16. Difference Amplifier (2/3) Voltage Divider @ p:

17. Difference Amplifier (3/3) Substitute: into: and simplify: If: Then:

18. Analyzing an OpAmp Circuit