Op-amp
From uCtrl.net
Contents |
Information
A operation amplifier is a circuit with high gain, mostly in the form of a integrated circuit. Op-amps are often fed with two symmetrical currents, one positive and one negative. The ideal op-amp would look like this: unlimited gain, unlimited output impedance and no input impedance. This is common: 100000 gain using DC current, often over 1M output impedance, below 100 ohms input impedance. Op-amps have two inputs, one inverted (-) and one normal (+).
Inverted
- Gain (AV) = -R2 / R1
- If R2 is 100K and R1 is 10K the gain is: -100 / 10 = -10
- At 0,5 volt on the input this gives 0.5 X -10 = -5v on the output.
Non-Inverted
- Gain (AV) = 1+(R2 / R1)
- If R2 is 100K and R1 is 10K the gain is: 1+ (1000/100) = 1 + 10
- At 0,5 volt on the input this gives 0.5 X 11 = 5.5v on the output.
Comparator
If Vin rises over or falls below Vref the output changes polarity.
Images
 Amplification of temperature signal |
