1. 1 Op-Amps

2. 2 Purpose ComparatorAmplifier An Op-Amp can be used to either compare two voltages and see which one is greater, or amplify a given voltage

3. 3 An Op-amp can act as a comparator to compare 2 voltages It indicates which is bigger by outputting a voltage (0V or 5V) Comparator

4. 4 The “-” input will act as the baseline If the “+” input becomes greater than the “-”, +V ss will come out the output Comparator

5. 5 Comparator Lab R2 R1

6. 6 Wiring Each Op-Amp chip contains multiple individual Op-Amps

7. 7 Wiring

8. 8

9. 9

10. 10 Wiring

11. 11 LAB Complete the Op-Amp lab in the book Lab: Operational Amplifier (Op-Amp) - Comparator

12. 12 In the amplifier setup of the circuit, the Op-Amp amplifies the V in and sends it out of V out The setup requires 2 resistors along with the Op-Amp Amplifier

13. 13 Amplifier – How it works There are two rules: Rule # 1: The voltage at “+” WILL equal the voltage at “-” Rule # 2: No current can enter an Op-Amp

14. 14 Suppose 0.0034V is sensed by V in Too little to be sensed by Arduino By Rule # 1, V A = V B = 0.0034 Voltage drop across R 1 = 0.0034V By V=IR, I 1 = 0.0000034 Amps Since no current can enter or exit the Op-Amp, it all must come from R 2, I 2 = 0.0000034 Amps By V=IR, V 2 = 3.4 V Amplifier – How it works A C B R 1 = 1,000Ω R 2 =1,000,000Ω D ground I 1 = 0.0000034 A I 2 = 0.0000034 A V 1 = 0.0034V

15. 15 Amplifier – How it works A C B R 1 = 1,000Ω R 2 =1,000,000Ω D ground

16. 16 LAB Complete the Op-Amp lab in the book Lab: Operational Amplifier (Op-Amp) – Amplifier