Clippers: Understanding Clippers

Clippers
Clippers

CLIPPERS:

Clippers are circuits which are used to clip or cut a part of the applied input signal. They have application in many electronics circuits. They are used in applications wherein only a part of input signal is usable, other portion is chopped off from the original signal.

Clippers: Series Clippers

To calculate the output waveform for a series clipper circuit, first we need to check the direction of the diode and understand whether the diode will conduct in the positive half cycle of the circuit or in the negative half cycle.( Positive half cycle is the period for which the sine wave is in between 0 to its positive peak value and Negative half cycle is the period for which the sine wave is in between 0 and its negative peak value). Now, for series clippers the diode conducts only when it is in forward bias, when in reverse bias,the diode acts at open circuit and no current flows through the circuit.

If the diode conducts in the positive half cycle, Apply KVL to the input side, we get,

                 Vin – Vd (+/-)Biasing battery = Vo

                Where….. Vin is the positive peak value of the input voltage

                       & Vd is the voltage drop across the diode

                       & Vo is the output voltage.

Let’s take an example:

Clippers: Series Negative Clipper

 

Negative Series Clipper circuit diagram
Negative Series Clipper circuit diagram

In the above ckt, we have input voltage as 5V p-p. (i.e. 2.5V for each half cycle).

The diode is connected in series with the input. A 1V biasing battery is applied to the diode which reverse biases the diode.

Applying KVL , we get, for time cycle 0-T1,

                    2.5 – 0.7 – 1 = Vo

                   i.e.      Vo = 2.5 – 1.7

                            Vo=0.8 V

So, the output will show just 0.8 V i.e. ranging from +1.7 V to +2.5 V, as the diode will not conduct in the second half cycle.

Negative Series Clipper output waveform
Negative Series Clipper output waveform

 

Clippers: Series Positive Clipper

Positive Series Clipper Circuit Diagram
Positive Series Clipper Circuit Diagram

In the above ckt, we have input voltage as 5V p-p. (i.e. 2.5V for each half cycle).

The diode is connected in series with the input but in opposite direction than the previous example. A 1V biasing battery is applied to the diode which forward biases the diode.

Applying KVL , we get,

                    -2.5 – 0.7 + 1 = Vo

                   i.e.      Vo = -2.5 +0.3

                            Vo= -2.2 V

So, the output will show just -2.2 V i.e. ranging from -0.3 V to -2.5 V.

Positive Series Clipper Output Waveform
Positive Series Clipper Output Waveform:

Clippers: Parallel Clippers

To calculate the output waveform for a parallel clipper circuit, first we need to check the direction of the diode and understand whether the diode will conduct in the positive half cycle of the circuit or in the negative half cycle.( Positive half cycle is the period for which the sine wave is in between 0 to its positive peak value and Negative half cycle is the period for which the sine wave is in between 0 and its negative peak value). Now, for parallel clippers the diode does not conduct when it is in forward bias, when in reverse bias,the diode acts at open circuit and we can say that the input voltage is the output voltage for the reverse biased cycle. Thus, seeing the configuration  

If the diode conducts in the positive half cycle, Apply KVL to the input side, we get,

                  Vd (+/-)Biasing battery = Vo

                Where…& Vd is the voltage drop across the diode

                        & Vo is the output voltage.

Let’s take an example:

 Clippers: Positive Parallel Clipper:

Positive Parallel Clipper Circuit Diagram
Positive Parallel Clipper Circuit Diagram

Here, Diode is connected in parallel to the output and a 1 V reverse bias is applied to it. Firstly, always calculate for the cycle for which the diode conducts.

So, in this case it is 0-T1 time period,

Since, Voltage in parallel is the same, the voltage across Diode is the output Voltage.

The diode conducts till 0.7 V, then, acts like a short Circuit. Thus, we obtain,

                  Vo =  Vd  (+/-) Biasing = 0.7 + 1 = 1.7 V

Now, For T1-T2,

The diode acts as an open circuit, hence, the output voltage is the same as input voltage.           Vo = Vin = -2.5 V.

Thus we get an output waveform between +1.7 V to -2.5 V.

Positive Parallel Clipper Output Waveform
Positive Parallel Clipper Output Waveform

Similarly for you can solve for various other configurations like

Clippers: Negative Parallel Clipper:

Negative Parallel Clipper Circuit Diagram
Negative Parallel Clipper Circuit Diagram

Here, Diode is connected in parallel (but in reverse direction than the previous one) to the output and a 1 V reverse bias is applied to it.

Firstly, always calculate for the cycle for which the diode conducts.

So, in this case it is T1-T2 time period,

Since, Voltage in parallel is the same, the voltage across Diode is the output Voltage.

The diode conducts till 0.7 V, then, acts like a short Circuit. Thus, we obtain,

                  Vo =  Vd  (+/-) Biasing =  -0.7 – 1 = -1.7 V

Now, For 0-T1,

The diode acts as an open circuit, hence, the output voltage is the same as input voltage.           Vo = Vin = 2.5 V.

Thus we get an output waveform between -1.7 V to +2.5 V.

Negative Parallel Clipper Output Waveform
Negative Parallel Clipper Output Waveform

Hope this article helped you, and improved your understanding of Clipper Circuits, you would like to checkout our other articles:

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