Virtual Short in Opamp
Sqare Wave Generator
741 Opamp PIN Diagram
Voltage follower- sample and hold
Lag and Lead Compensators
Precision diode- Halfwave Rectifier
Peak and Zero Crossing Detector
Log and Anti-Log Amplifiers
Inverting- Non inverting Amplifiers
Voltage follower is one in which the output exactly follows the input. The circuit shown below acts as ideal DC voltage follower.
The output exactly follows the input because the two inputs are tied together virtually, hence Vout = Vin.
Sample and hold circuit
The sample and hold circuit using op amp is shown below
The switching element will be a electronic device such as MOSFET with control voltage applied to gate consisting of a train of pulses. Whenever the switch is closed i.e. MOSFET is on, the capacitor charges to the voltage at the input with a time constant equal to on resistance of control device *C. After the switch is opened (MOSFET is off) the capacitor holds the charge and hence the voltage across capacitor cannot change since it does not have any path to discharge. Then the voltage across the capacitor is replicated at the output by a voltage follower.