Q. Write short note on a negative clamper ?

A circuit which places the negative peak of a signal at a desired level is known as a negative clamper

(1). During the positive half-cycle of the input signal ,the diode is forward biased. Therefore ,the diode behaves as a short.The charging time constant (RC)is very small so that the capacitor will charge to V volts very quickly.During this interval output voltage is directly across the short circuit.Therefore Vout =0.

(2). During the negative half-cycle the diode is reverse biased and behaves as an open circuit.since the discharging time constant is much greater than the time period of the input signal,the capacitor remains almost fully charged to V volts during the off time of the diode.