Q. What is a positive clipper? Explain its action with the help of a circuit.

A positive clipper is the circuit which is used to cut off the positive half cycle. The circuit will be as shown below. The output voltage V0 is that which is dropped across R. During the positive half cycle of the signal (i) voltage acts as an open switch. Hence al the applied voltage drops across D and none across R.So there is no output signal voltage. Thus the positive half cycle is clipped away as shown in (ii)

   During the negative half cycle, terminal B is positive and so it forward biases D which acts as a short. Hence there is no voltage drops across D.Consequently ,all the applied signal voltage drops across R and none across D.As a result,the negative half cycle of the input signal  is allowed to pass through the clipper circuit.Hence the circuit acts as a positive clipper.

Here during the positive half cycle ,it reverse biases D1and during the negative half cydleit forward biases D1.