# Types of Clippers and Clampers with Applications

Typical projects of electronics operate at different electrical signal ranges and therefore, for these electronic circuits, it is intended to maintain the signals in a particular range in order to obtain the desired outputs. To receive the output at expected voltage levels, we have versatile tools in the electrical domain and those are called Clippers and Clampers. This article shows a clear description of clippers and clampers, their differences, and how they operate as per the expected voltage levels.

## What are Clippers and Clampers?

Clippers and Clampers in electronics are widely used in the operation of analog television receivers and FM transmitters. The variable-frequency interference can be removed by using the clamping method in television receivers, and in FM transmitters, the noise peaks are limited to a specific value, above which the excessive peaks can be removed by using the clipping method.

### What is a Clipper Circuit?

An electronic device that is used to evade the output of a circuit to go beyond the preset value (voltage level) without varying the remaining part of the input waveform is called a Clipper circuit.

An electronic circuit that is used to alter the positive peak or negative peak of the input signal to a definite value by shifting the entire signal up or down to obtain the output signal peaks at the desired level is called a Clamper circuit.

There are different types of clippers and clampers circuits as discussed below.

### Working of Clipper Circuit

The clipper circuit can be designed by utilizing both the linear and nonlinear elements such as resistors, diodes, or transistors. As these circuits are used only for clipping input waveform as per the requirement and for transmitting the waveform, they do not contain any energy storing element like a capacitor. In general, clippers are classified into two types: Series Clippers and Shunt Clippers.

#### Series Clippers

Series clippers are again classified into series negative clippers and series positive clippers which are as follows:

Series Negative Clipper

The above figure shows a series of negative clippers with their output waveforms. During the positive half cycle, the diode (considered as an ideal diode) appears in the forward biased and conducts such that the entire positive half cycle of input appears across the resistor connected in parallel as an output waveform.

During the negative half cycle, the diode is in reverse biased. No output appears across the resistor. Thus, it clips the negative half cycle of the input waveform, and therefore, it is called a series of negative clipper.

Series Negative Clipper with Positive Vr

Series negative clipper with positive reference voltage is similar to the series negative clipper, but in this a positive reference voltage is added in series with the resistor. During the positive half cycle, the diode starts conducting only after its anode voltage value exceeds the cathode voltage value. Since cathode voltage becomes equal to the reference voltage, the output that appears across the resistor will be as shown in the above figure.

The series negative clipper with a negative reference voltage is similar to the series negative clipper with a positive reference voltage, but instead of positive Vr here a negative Vr is connected in series with the resistor, which makes the cathode voltage of the diode a negative voltage.

Thus during the positive half cycle, the entire input appears as output across the resistor, and during the negative half cycle, the input appears as output until the input value will be less than the negative reference voltage, as shown in the figure.

#### Series Positive Clipper

The series positive clipper circuit is connected as shown in the figure. During the positive half cycle, the diode becomes reverse-biased, and no output is generated across the resistor, and during the negative half cycle, the diode conducts and the entire input appears as output across the resistor.

Series Positive Clipper with Negative Vr

It is similar to the series positive clipper in addition to a negative reference voltage in series with a resistor; and here, during the positive half cycle, the output appears across the resistor as a negative reference voltage.

During the negative half-cycle, the output is generated after reaching a value greater than the negative reference voltage,  as shown in the above figure.

Instead of a negative reference voltage, a positive reference voltage is connected to obtain a series positive clipper with a positive reference voltage. During the positive half cycle, the reference voltage appears as an output across the resistor, and during the negative half cycle, the entire input appears as output across the resistor.

### Shunt Clippers

Shunt clippers are classified into two types: shunt negative clippers and shunt positive clippers.

#### Shunt Negative Clipper

Shunt negative clipper is connected as shown in the above figure. During the positive half cycle, the entire input is the output, and during the negative half cycle, the diode conducts causing no output to be generated from the input.

Shunt Negative Clipper with Positive Vr

A series positive reference voltage is added to the diode as shown in the figure. During the positive half cycle, the input is generated as output, and during the negative half cycle, a positive reference voltage will be the output voltage as shown below.

Shunt Negative Clipper with Negative Vr

Instead of the positive reference voltage, a negative reference voltage is connected in series with the diode to form a shunt negative clipper with a negative reference voltage. During the positive half cycle, the entire input appears as output, and during the negative half cycle, a reference voltage appears as output as shown in the below figure.

#### Shunt Positive Clipper

During the positive half cycle, the diode is in conduction mode and no output is generated; and during the negative half cycle; the entire input appears as output as the diode is in reverse bias as shown in the below figure.

Shunt Positive Clipper with Negative Vr

During the positive half cycle, the negative reference voltage connected in series with the diode appears as output; and during the negative half cycle, the diode conducts until the input voltage value becomes greater than the negative reference voltage and the corresponding output will be generated.

Shunt Positive Clipper with Positive Vr

During the positive half cycle the diode conducts causing the positive reference voltage to appear as output voltage; and, during the negative half cycle, the entire input is generated as the output as the diode is in reverse biased.

In addition to the positive and negative clippers, there is a combined clipper that is used for clipping both the positive and negative half-cycles as discussed below.

Positive-Negative Clipper with Reference Voltage Vr

The circuit is connected as shown in the figure with a reference voltage Vr, diodes D1 & D2. During the positive half cycle, the diode D1 conducts causing the reference voltage connected in series with D1 to appear across the output.

During the negative cycle, the diode D2 conducts causing the negative reference voltage connected across the D2 to appear as corresponding output.

#### Clipper Circuits by Clipping both the Half Waves

clipper circuits by clipping both the half waves are discussed below.

For the Positive Half Cycle

Here, the cathode side of the D1 diode is connected to positive DC voltage and the anode receives a varied positive voltage. In the same way, the anode side of the D2 diode is connected to negative DC voltage and the cathode side receives a varied positive voltage. At the time of the positive half cycle, the D2 diode will be totally in the reverse biased condition. Here, the equations are represented as follows:

When the input voltage is less than Vdc1 + Vd1 when the diodes are in reverse bias condition, then the output voltage is Vin (input voltage)

When the input voltage is greater than Vdc1 + Vd1 when the D1 is in forwarding bias and D2 is in reverse bias condition, then the output voltage is Vdc1 + Vd1

For the Negative Half Cycle

Here, the cathode side of the D1 diode is connected to positive DC voltage and the anode receives a varied negative voltage. In the same way, the anode side of the D2 diode is connected to negative DC voltage and the cathode side receives a varied negative voltage. At the time of the positive half cycle, the D2 diode will be totally in the reverse biased condition. Here, the equations are represented as follows:

When the input voltage is less than Vdc2 + Vd2 when the diodes are in reverse bias condition, then the output voltage is Vin (input voltage)

When the input voltage is greater than Vdc2 + Vd2 when the D2 is in forwarding bias and D1 is in reverse bias condition, then the output voltage is (-Vdc2 – Vd2)

In the clipper circuits clipping both the half-waves, the positive and negative clipping ranges can be separately varied which means +ve and -ve voltage levels can be different. These are also termed as parallel dependent clipper circuits. It is operated using two voltage sources and two diodes that are connected in the opposite way to each other.

#### Clipping Through Zener Diode

This is the other type of clipping circuit

Here, the Zener diode functions as biased diode clipping where the biasing voltage is the same as the voltage at the diode breakdown condition. In this type of clipping circuit, at the time of the +ve half cycle, the diode is in reverse biased condition, and the signal clips at the condition of Zener voltage.

And at the time of the -ve half cycle, the diode functions normally condition where the Zener voltage is 0.7V. In order to clip both the half cycles of the waveform, then the diodes are connected like back-to-back diodes.

### What is Meany by Clamper?

The clamper circuits are also called DC restorers. These circuits are especially used to shift the applied waveforms to above or below levels of the DC reference voltage without showing the impact on the shape of the waveform. This shifting tends to modify the Vdc level of the applied wave. The peak levels of the wave can be shifted through the diode clampers so these are even termed as level shifters. In regard to this, clamper circuits are mainly categorized as positive and negative clampers.

### Working of Clamper Circuit

The positive or negative peak of a signal can be positioned at the desired level by using the clamping circuits. As we can shift the levels of peaks of the signal by using a clamper, hence, it is also called a level shifter.

The clamper circuit consists of a capacitor and diode connected in parallel across the load. The clamper circuit depends on the change in the time constant of the capacitor. The capacitor must be chosen such that, during the conduction of the diode, the capacitor must be sufficient to charge quickly and during the nonconducting period of the diode, the capacitor should not discharge drastically. The clampers are classified as positive and negative clampers based on the clamping method.

#### Negative Clamper

During the positive half cycle, the input diode is in forwarding bias- and as the diode conducts-capacitor gets charged (up to peak value of input supply). During the negative half-cycle, the reverse does not conduct and the output voltage becomes equal to the sum of the input voltage and the voltage stored across the capacitor.

Negative Clamper with Positive Vr

It is similar to the negative clamper, but the output waveform is shifted towards the positive direction by a positive reference voltage. As the positive reference voltage is connected in series with the diode, during the positive half cycle, even though the diode conducts, the output voltage becomes equal to the reference voltage; hence, the output is clamped towards the positive direction as shown in the below figure.

Negative Clamper with Negative Vr

By inverting the reference voltage directions, the negative reference voltage is connected in series with the diode as shown in the above figure. During the positive half cycle, the diode starts conduction before zero, as the cathode has a negative reference voltage, which is less than that of zero and the anode voltage, and thus, the waveform is clamped towards the negative direction by the reference voltage value.

#### Positive Clamper

It is almost similar to the negative clamper circuit, but the diode is connected in the opposite direction. During the positive half cycle, the voltage across the output terminals becomes equal to the sum of the input voltage and capacitor voltage (considering the capacitor as initially fully charged).

During the negative half cycle of the input, the diode starts conducting and charges the capacitor rapidly to its peak input value. Thus the waveforms are clamped towards the positive direction as shown above.

Positive Clamper with Positive Vr

A positive reference voltage is added in series with the diode of the positive clamper as shown in the circuit. During the positive half cycle of the input, the diode conducts as initially, the supply voltage is less than the anode positive reference voltage.

If once the cathode voltage is greater than the anode voltage then the diode stops conduction. During the negative half cycle, the diode conducts and charges the capacitor. The output is generated as shown in the figure.

Positive Clamper with Negative Vr

The direction of the reference voltage is reversed, which is connected in series with the diode making it a negative reference voltage. During the positive half cycle, the diode will be non-conducting, such that the output is equal to capacitor voltage and input voltage.

During the negative half cycle, the diode starts conduction only after the cathode voltage value becomes less than the anode voltage. Thus, the output waveforms are generated as shown in the above figure.

### Clippers and Clampers using Op-Amp

So, based on op-amp, clippers and clampers are mainly classified into two types and those are positive and negative types. Let us know the operation of clipper and clamper using op-amp.

#### Clippers Using Op-Amp

In the below circuit, a sine wave of Vt voltage is applied to the op-amp’s non-inverting end and the Vref value can be varied by changing the R2 value. The operation is explained as follows for the positive clipper:

• When the Vi (input voltage) is minimal than that of Vref, then the conduction in D1 takes place and the circuit functions as a voltage follower. So, the Vo remains the same as the input voltage for the condition Vi < Vref
• When the Vi (input voltage) is more than that of Vref, then there will be no conduction, and the circuit functions as an open-loop because the feedback was not in a closed way. So, the Vo remains the same as a reference voltage for the condition Vi > Vref

For the negative clipper, the operation is

In the below circuit, a sine wave of Vt voltage is applied to the op-amp’s non-inverting end and the Vref value can be varied by changing the R2 value.

• When the Vi (input voltage) is more than that of Vref, then the conduction in D1 takes place and the circuit functions as a voltage follower. So, the Vo remains the same as the input voltage for the condition Vi > Vref
• When the Vi (input voltage) is less than that of Vref, then there will be no conduction, and the circuit functions as an open-loop because the feedback was not in a closed way. So, the Vo remains the same as the reference voltage for the condition Vi < Vref.

#### Clampers using Op-Amp

The operation of the positive clamper circuit is explained as follows:

Here, a sine wave is applied to the op-amp’s inverting end using a capacitor and the resistor. This corresponds that the AC signal is applied to the inverting terminal of the op-amp. Whereas Vref is applied to the op-amp non-inverting end.

The level of the Vref can be selected by modifying the value of R2. Here, Vref is a positive value, and the output is the Vi + Vref where this corresponds that clamper circuit generates the output where the Vi will have an upward vertical shift taking Vref as the reference voltage.

And in the negative clamper circuit, a sine wave is applied to the op-amp’s inverting end using a capacitor and the resistor. This corresponds that the AC signal is applied to the inverting terminal of the op-amp. Whereas Vref is applied to the op-amp non-inverting end.

The level of the Vref can be selected by modifying the value of R2. Here, Vref is a negative value, and the output is the Vi + Vref where this corresponds that clamper circuit generates the output where the Vi will have a downward vertical shift taking Vref as the reference voltage.

### Differences between the Clippers and Clampers

This section clearly explains the key differences between clipper and clamper circuits

 Feature Clipper Circuit Clamper Circuit Clippers and Clampers definition Clipper circuit functions to delimit the amplitude range of the output voltage Clamper circuit functions to shifts the DC voltage level to the output Output waveform The shape of the output waveform can be changed to rectangular, triangular, and sinusoidal The output waveform shape is the same as the applied input waveform DC Voltage Levels Stays the same There will be a shift in the DC level Output Voltage Levels It is minimal than that of input voltage level It is the multiple of input voltage level Component for Energy Storage There is no need for additional components for storing energy It needs a capacitor for the storage of energy Applications Used in multiple devices such as receivers, amplitude selectors, and transmitters Employed in sonar and radar systems

### Applications of Clippers and Clampers

The applications of clippers are:

• They are frequently used for the separation of synchronizing signals from the composite picture signals.
• The excessive noise spikes above a certain level can be limited or clipped in FM transmitters by using the series clippers.
• For the generation of new waveforms or shaping the existing waveform, clippers are used.
• The typical application of a diode clipper is for the protection of transistors from transients, as a freewheeling diode connected in parallel across the inductive load.
• A frequently used half-wave rectifier in power supply kits is a typical example of a  clipper. It clips either positive or negative half-wave of the input.
• Clippers can be used as voltage limiters and amplitude selectors.

The applications of clampers are:

• The complex transmitter and receiver circuitry of the television clamper is used as a baseline stabilizer to define sections of the luminance signals to preset levels.
• Clampers are also called direct current restorers as they clamp the waveforms to a fixed DC potential.
• These are frequently used in test equipment, sonar, and radar systems.
• For the protection of the amplifiers from large errant signals, clampers are used.
• Clampers can be used for removing the distortions
• For improving the overdrive recovery time clampers are used.
• Clampers can be used as voltage doublers or voltage multipliers.

These are all the detailed applications of both clippers and clampers.

Clippers and clampers circuits are used for molding a waveform to a required shape and specified range. The clippers and clampers discussed in this article can be designed using diodes. Do you know any other electrical and electronic elements with which clippers and clampers can be designed? If you have understood this article in-depth, give your feedback, and post your queries and ideas as comments in the below section.