1. Operational Amplifier 555 Timers Term 4 Projects

2. Operational Amplifier An Op Amp is made of: 1) Gain "Block" 2) Feedback 3) A Network

3. Gain "Block" + -

4. Feedback + -

5. Network + - R2R2 R1R1

6. Gain G = R2R2 R1R1

7. “Stair-stepping” Gain

10. 555 Timer  Timing Circuit  Oscillator  Controllable

11. 8 Pin DIP DIP – Dual Inline Package Pin

12. 555 Timer Pins Gnd Trigger Output Reset Vcc Discharge Threshold Control Voltage 1 2 3 4 8 7 6 5

13. Typical Wiring

15. T 2 =0.693(R b )C (Disharge) T 1 =0.693(R a +R b )C (Charge) T1T1 T2T2 Pin 3 Output

16. Frequency Cycles per Second Hertz - Hz F = 1/T 555 Timer F = 1/(T 1 + T 2 )

17. Example R a = 6.8KΩ R b = 6.8KΩ C = 0.15µf

18. T 1 =0.693(6.8kΩ+6.800k) 0.15μf T 1 = 1.41ms T 2 =0.707 ms T 2 =0.693(6.8kΩ) 0.15μf F = 1/(T 1 + T 2 ) F = 1/(1.41 ms + 0.707 ms) F = 1/(0.00141s + 0.000707s) F = 472Hz T 1 =0.693(6800Ω+6800Ω) 0.00000015f T 2 =0.693(6800Ω) 0.00000015f