Initially the switch is open..... the output voltage follows the input voltage... as soon as the switch is closed the output drops to 0v. But voltage across capacitor (Vc) now follows the input. If the switch is now opened at particular time when Vc != 0, the output voltage is shifted by some DC value. This example illustrates the working of both capacitor and Clamping.
Capacitor stores DC but allows AC.
Clamper: Output is clamped to a Particular DC level.
Some constraints:
1. Since the switch is operated by us, the frequency of input is kept minimum, so that switching can be done at more accurate value of Vc.
2. Since capacitor is not ideal, to mimic the ideality of capacitor, a very high value of resistor is connected across the output.
