Clipper Circuits – Features & Applications

A clipper also referred to as a limiter is a circuit which removes the peak of a waveform. A clipper consists of diodes, resistors and sometimes DC sources to clip or limit the output to a certain level.

The input-output characteristics of clipper circuits are typically similar to those of the forward-biased and reverse-biased diode characteristics except that the output is clipped to a certain level.

Figure 1.0 below shows a clipper circuit and its input-output characteristics where the diode does not conduct for v_in < 0.6 V and so v_out = v_in. The diode conducts for v_in ≥ 0.7 V.

Figure 1.1 below shows a clipper circuit and its input-output characteristics where the diode does not conduct for v_in > -0.6 V but it conducts for v_in ≤  -0.7 V and thus v_out ≈ -0.7 V.

Figure 1.2 below shows a clipper circuit with two diodes in parallel with opposite polarities. This is in fact a combination of two clipper circuits discussed above. Both diodes are not conducting when -0.7 ≤ v_in ≤ 0.7 and for this interval v_out = v_in. Outside this interval, one or the other diode conducts. This circuit is called a hard limiter.

To raise the limit level to a value other than vout ≈ ±0.7 V, a DC source can be placed in series with the diode as illustrated below:

Applications of Clipper Circuits

Clipper circuits are used in applications where there is a need to limit the input to another circuit so that the latter would not be damaged.

Examples of uses of clipper circuits are as follows:

• They are used in radars and digital computers where it is necessary to remove signal voltages above or below a specified voltage level.
• They are also used in radio receivers’ communication circuits where noise pulses that rise well above the signal amplitude are clipped down to the desired level.

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