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Operational Amplifier 555 Timers. Term 4 Projects. Operational Amplifier. An Op Amp is made of: . 1) Gain "Block". 2) Feedback . 3) A Network. -. +. Gain "Block". -. +. Feedback. Network. R 2. R 1. -. +. R 2. G =. R 1. Gain. “Stair-stepping” Gain. 555 Timer. Timing Circuit.
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Operational Amplifier555 Timers Term 4 Projects
Operational Amplifier An Op Amp is made of: 1) Gain "Block" 2) Feedback 3) A Network
- + Gain "Block"
- + Feedback
Network R2 R1 - +
R2 G = R1 Gain
555 Timer • Timing Circuit • Oscillator • Controllable
Pin 8 Pin DIP DIP – Dual Inline Package
1 8 2 7 3 6 4 5 555 Timer Pins Vcc Gnd Trigger Discharge Output Threshold Control Voltage Reset
Typical Wiring
Pin 3Output T1 T2 T1=0.693(Ra+Rb)C (Charge) T2=0.693(Rb)C (Disharge)
Frequency • Cycles per Second • Hertz - Hz • F = 1/T • 555 Timer F = 1/(T1 + T2)
Ra = 6.8KΩ Example Rb = 6.8KΩ C = 0.15µf
T1=0.693(6.8kΩ+6.800k) 0.15μf T1=0.693(6800Ω+6800Ω) 0.00000015f T1= 1.41ms T2=0.693(6.8kΩ) 0.15μf T2=0.693(6800Ω) 0.00000015f T2=0.707 ms F = 1/(T1+ T2) F = 1/(1.41 ms + 0.707 ms) F = 1/(0.00141s + 0.000707s) F = 472Hz