Series clipper

Clippers

Series clipper

The response of the series configuration to a variety of alternating waveforms is provided although first introduced as a half-wave rectifier (for sinusoidal waveforms); there are no boundaries on the type of signals that can be applied to a clipper. The addition of a dc supply can have a pronounced effect on the output of a clipper. Our initial discussion will be limited to ideal diodes, with the effect of VT reserved for a concluding example.

Circuit diagram:

There is no general procedure for analyzing networks such as the type in Fig but there are a few thoughts to keep in mind as you work toward a solution. Make a mental sketch of the response of the network based on the direction of the diode and the applied voltage levels. For the network, the direction of the diode suggests that the signal must be positive to turn it on. The dc supply further requires that the voltage be greater than V volts to turn the diode on.

The negative region of the input signal is ―pressuring the diode into the ―off state, supported further by the dc supply. In general, therefore, we can be quite sure that the diode is an open circuit (―off

state) for the negative region of the input signal. Determine the applied voltage (transition voltage) that will cause a change in state for the diode: For an input voltage greater than V volts the diode is in the short-circuit state, while for input voltages less than V volts it is in the open-circuit or ―off state.

Determining the transition level for the circuit

Be continually aware of the defined terminals and polarity of Vo. When the diode is in the short-circuit state, such as shown in Fig. , the output voltage V_o can be determined by applying Kirchhoff‘s

voltage law in the clockwise direction V_i – V – V_o (CW direction)

It can be helpful to sketch the input signal above the output and determine the output at instantaneous values of the input:

It is then possible that the output voltage can be sketched from the resulting data points of as demonstrated. Keep in mind that at an instantaneous value of vi the input can be treated as a dc supply of that value and the corresponding dc value (the instantaneous value) of the output determined. For instance, at V_i = V_m for the network, the network to be analyzed appears. For V_m > V the diode is in the short-circuit state and V_o = V_m - V.

Determining Levels Of V_o

Determining V_o When V_i = V_m

At the V_i = V_m diodes change state; at V_i = – V_m, V_o =0 V; and the complete curve for V_o can be sketched.