 Clamping can be used to adapt an input signal to a device that cannot make use of or may be damaged by the signal range of the original input.During the first negative phase of the AC input voltage, the capacitor in a positive clamper circuit charges rapidly.As "V"in becomes positive, the capacitor serves as a voltage doubler; since it has stored the equivalent of "V"in during the negative cycle, it provides nearly that voltage during the positive cycle.