CLIPPING AND CLAMPING CIRCUITS

                                                 CLIPPING CIRCUIT 

  • Diode Clipper is a wave shaping circuit that takes an input waveform and clips or cuts off its top half, bottom half or both halves together.This clipping of the input signal produces an output waveform that resembles a flattened version of the input.
  • It is also known as a limiter.
  • Clippers are used to perform one of the following two functions:
    • Changing the shape of a waveform :
      • For example, a clipper can be used to convert a sine wave into rectangular wave, square wave etc.
    • Circuit Transient protection :
      • A transient is a sudden current or voltage rise that has an extremely short duration.
      • In such cases, a clipper diode can be used to prevent the transient from reaching that circuit.
  • Depending on the features of the diode, the positive or negative region of the input signal is “clipped” off and accordingly the diode clippers may be positive or negative clippers.

Positive Clipper

Negative Clipper

  • Different levels of clipping can be obtained by varying the amount of voltage of the battery and also interchanging the positions of the diode and resistor.

 

                                                   CLAMPING CIRCUIT 

  • The Clamping circuit or clamper keeps the amplitude of the output signal same as that of the input signal except that the D.C. level (offset) has been changed.
  • Simply it is a circuit that places either the positive or negative peak of a signal at a desired d.c. level is known as a clamping circuit.
  • The clamper is also referred to as an IC restorer and ac signal level shifter. The dc component is simply added or subtracted to/from the input signal.
  • Points to be noted about Clamper circuits :
    1. The shape of the waveform will be the same, but its level is shifted either upward or downward.
    2. There will be no change in the peak-to-peak or rms value of the wave­form.
    3. The values of the resistor R and capacitor C affect the waveform and are determined from the time constant RC.
    4. In a good clamper circuit, the circuit time constant t = RC should be at least ten times the time period of the input signal voltage so that the voltage across the capacitor C does not change significantly during the time interval the diode is non-conducting.