Diode Clipper vs. Clamper Circuits: Key Differences Explained

This article explains the basic differences between diode clipper and clamper circuits. Both circuits use diodes to modify input waveforms in a desired manner.

Clipper Circuits

Clippers are diode-based networks designed to “clip” off a portion of the input waveform without affecting the remaining part of the alternating waveform. There are two main types: series and parallel clippers.

Figure 1: Clipper Circuits

• Series Clipper: The diode is connected in series with the load.
• Parallel Clipper: The diode is connected in parallel with the load.

How Clippers Work:

In the circuit example in Figure 1:

• During the positive half of the input waveform, the diode conducts, and this portion of the signal is passed to the output (for the series clipper). In the parallel clipper, the diode conducts and grounds the signal during this time.
• During the negative half of the waveform, the diode does not conduct (in series configuration), effectively clipping off this portion. In the parallel clipper, the diode becomes open, allowing the negative portion to appear at the output.
• The result is an output waveform that only contains the positive half (or in the parallel configuration, only contains the negative half) of the original input.

Clamper Circuits

Clampers, as the name suggests, “clamp” the input signal, shifting its DC level to a different position.

Figure 2: Clamper Circuit

A typical clamper circuit consists of a diode, a capacitor, and a resistor.

How Clampers Work:

Consider the clamper circuit in Figure 2:

• Interval 0 to T/2: The diode is in the ON state, effectively creating a short circuit. The output voltage (Vo) is approximately 0 volts.
• Interval T/2 to T: The diode is in the OFF state (open circuit) and does not conduct. Applying Kirchhoff’s Voltage Law (KVL) to the inner loop yields: -V - V - Vo = 0, thus Vo = -2V.
• The result is that the entire waveform is shifted downwards by a voltage equal to V, clamping the lowest point to -2V.

Key Differences Summarized