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 vin < 0.6 V and so vout = vin. The diode conducts for vin ≥ 0.7 V.
Figure 1.1 below shows a clipper circuit and its input-output characteristics where the diode does not conduct for vin > -0.6 V but it conducts for vin ≤ -0.7 V and thus vout ≈ -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 ≤ vin ≤ 0.7 and for this interval vout = vin. 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.
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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.
You may also read:
- The Varactor Diode
- PIN Diode – Features & Applications
- Unijunction Transistor Features and Operation
- Bipolar Junction Transistors (BJT)
- How Photoelectric Effect Impacts p-n Junctions
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