What are Clipper Circuits?

Introduction

Clipper circuits are electronic circuits that are used to clip or limit the amplitude of a waveform. They are commonly used in electronic devices to protect components from voltage spikes and to shape waveforms for various applications. In this article, we will explore the different types of clipper circuits and their applications. A clippers circuit is also known as a diode limiter. It is an essential component in electronic circuits that allows us to control and manipulate signals. It is primarily used to limit or clip the amplitude of a waveform, hence the name "clippers." This circuit is commonly employed in various applications, such as audio systems, communication devices, and power supplies. Mainly, a clipper circuit consists of a diode and a resistor.  The diode acts as a one-way valve for current flow which allows it to conduct in only one direction. When the input signal exceeds a certain threshold, then the diode starts to conduct and limits the output voltage to a predetermined level. This process effectively "clips" the waveform and removes any portions that exceed the desired limit.

Clipper circuits are incredibly versatile and can be configured in various ways to achieve specific results. For instance, a series clipper circuit is used to clip either the positive or negative peaks of a waveform, while a shunt clipper circuit clips both the positive and negative peaks. By adjusting the resistance and diode arrangement, we can customize the clipping threshold and shape of the output waveform. These circuits serve to prevent distortion caused by excessive signal amplitudes, ensuring a clean and undistorted sound output. Additionally, clipper circuits are employed in power supplies to safeguard electronic devices from voltage spikes and surges. They constitute an essential component in electronic circuits, allowing precise control and manipulation of signals. Through the selective limitation of waveform amplitudes, clipper circuits ensure the desired output while averting distortion or damage to connected devices. Whether in audio systems or power supplies, clipper circuits play a crucial role in maintaining signal integrity and safeguarding electronic components.

Classification of Clipper circuits

Clipper circuits are electronic circuits used to clip or limit the amplitude of a signal. They are commonly used in electronic devices to protect sensitive components from excessive voltage or to shape the waveform of a signal. Clipper circuits are broadly classified based on their functionality and the portion of the waveform they clip. Here are the classifications of clipper circuits:

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Series positive Clipper circuit

The series positive clipper circuit consists of a diode connected in series with a resistor and a load. When the input signal is applied, the diode conducts only when the voltage across it is greater than the forward voltage drop. This means that any positive voltage above the forward voltage drop of the diode will be clipped off, resulting in a waveform with reduced amplitude.

Series Positive Clipper CircuitLooking at how a series positive clipper is set up, you'll notice that the diode is part of the output path, and that's why it's called "series." When the input waveform has its positive part, it makes the diode act like an open switch because of reverse biasing. This means the entire input voltage is focused on the diode, and there's no output voltage during the positive part of the input waveform. On the flip side, during the negative part of the input waveform, the diode switches to a forward-biased state, becoming a closed switch and causing almost no voltage drop. This results in the input voltage showing up across the resistor and becoming the output of the circuit. Simply put, the series positive clipper gets rid of the positive peaks in the input signal by how the diode behaves.

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Series negative clipper circuit

This circuit is designed to clip or limit the negative portion of a waveform, allowing only the positive portion to pass through. The series negative clipper circuit consists of a diode connected in series with a load resistor. When the input signal is applied, the diode allows the positive portion of the waveform to pass through, while blocking the negative portion. This results in a clipped waveform that only contains the positive peaks.

The picture shows a series negative clipping circuit, and how it works is pretty simple. When the input waveform has its positive part, the diode is forward-biased, making a pathway or a closed circuit. This lets the current go through the resistor in the circuit. However, when the input waveform goes negative, the diode switches to a reverse-biased state, acting like turning it into an open switch. In this setup, no current can go through the circuit during the negative part of the input waveform. So, during this negative part, there's no output produced. Basically, the series negative clipping circuit only lets the positive part of the signal go through while blocking the negative part when it's working.

Series positive clipper circuit with bias

This circuit is designed to clip the positive portion of the input signal while maintaining a certain bias level. The series positive clipper circuit with bias consists of a diode and a biasing resistor connected in series. The input signal is applied across the diode and the resistor. When the input signal voltage is positive and greater than the bias voltage, the diode conducts and the output voltage across the load resistor is equal to the bias voltage. This effectively clips the positive portion of the input signal. The bias resistor is used to set the bias voltage level. By adjusting the value of the bias resistor, the desired bias voltage can be obtained. This allows for customization of the clipping level and ensures that the clipped portion of the waveform remains at the desired bias level.

Looking at the circuit above, we can see that the diode is in a forward bias condition due to the battery. However, during the positive half of the input waveform, the diode switches to a reverse-biased state.

The diode conducts as long as the supply voltage is less than the battery potential. Since the battery potential is stronger than the supply voltage, the signal appears during the positive half of the output waveform. But when the supply voltage becomes greater than the battery potential, the diode becomes reverse-biased. As a result, no more current flows through the diode. For the negative half cycle of the input waveform, the diode is forward biased with respect to both the supply voltage and the battery potential. This setup allows us to achieve a complete negative half cycle in the output waveform.

Shunt positive Clipper circuits

This circuit is used to clip or limit the positive portion of an input waveform. So how does a shunt positive clipper circuit work? Well, it consists of a diode and a resistor connected in parallel. The diode serves as the clipping element, while the resistor limits the current flow. When the input voltage exceeds the forward bias voltage of the diode, it conducts and allows current to flow through the resistor, effectively clipping the positive portion of the waveform.

Now, let's take a look at the shunt clippers circuit shown below.

In this setup, the diode is connected in parallel with the load. Therefore, its working principle is the exact opposite of series clippers. In shunt positive clippers, the output signal is visible only when the diode is reverse biased.

During the positive half of the input signal, the diode becomes forward biased, allowing current to flow through it. However, due to the parallel arrangement of the diode and the load, no current is observed at the load. Consequently, there is no output waveform during the positive half. Conversely, during the negative half of the input signal, the diode becomes reverse biased. As a result, no current flows through it, and the output current is observed at the load. Therefore, for the negative half of the input, the entire negative half appears at the output.

Shunt negative Clippers circuits

A shunt negative clipper circuit consists of a diode and a resistor connected in parallel. The diode acts as a one-way valve, allowing current to flow in only one direction. When the input voltage is positive, the diode is reverse-biased and does not conduct any current. However, when the input voltage is negative, the diode becomes forward-biased, allowing current to flow through it. By placing a resistor in parallel with the diode, we can control the amount of current that flows through the diode when it is forward-biased. This resistor determines the clipping level of the circuit. If the resistor value is high, the circuit will clip at a higher voltage level, removing more of the negative portion of the waveform.

Let's explore the circuit illustrated below, depicting shunt negative clippers.

In the case of negative shunt clippers, during the positive half of the input, the diode becomes reverse biased. Consequently, no current flows through it, and the output current is observed at the load.

Therefore, the output signal is obtained for the positive half of the input signal. However, during the negative half of the input signal, the diode becomes forward biased. As a result, no load current is achieved, leading to no output being observed for the negative half of the input signal.

Shunt positive clipper circuits with bias

Let's delve into the scenarios of positive and negative biasing in shunt positive clipper circuits, taking a similar approach as we did with series clippers featuring bias.

Shunt positive clipper circuits with biasFor positively biased circuits: During the positive half of the input cycle, the diode experiences forward biasing. However, an intriguing interplay occurs as the battery potential simultaneously induces a reverse-biased state in the diode. As long as the battery potential exceeds the supply voltage, the diode remains in a reverse-biased condition, thanks to the battery potential. This arrangement limits the flow of current through the diode, allowing the current to instead pass through the load. Consequently, a signal is observable at the output. However, as the input voltage surpasses the battery potential, the diode transitions to a forward-biased state due to the supply voltage, enabling current to flow through it and resulting in no output.

Dual clipper circuits

When there's a need to remove a certain part of both the positive and negative halves of a signal, we use dual clipper circuits.

Let's take a look at the circuit of a dual clipper shown below:

During the positive half of the input cycle, diode D1 becomes forward-biased due to the supply voltage but is in a reverse-bias state due to the battery potential VB1. Simultaneously, diode D2 is in reverse bias due to both the supply voltage and battery potential VB2.

As long as the battery voltage exceeds the supply voltage, D1 will be in a reverse-biased state, and D2 is already in a reverse bias condition. This setup allows a signal to be achieved at the output. However, when the supply voltage exceeds the battery potential, D1 becomes forward-biased. As a result, no further signal for the positive half is achieved in this case. During the negative half of the input cycle, diode D1 will be reverse-biased due to both the supply voltage and battery potential. On the flip side, diode D2 will be forward-biased by the supply voltage but is reverse-biased by the battery potential VB2.

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Applications of Clipper circuits

Clipper circuits find wide applications in voltage regulation, signal processing, audio amplification, overvoltage protection, and PWM applications. Their ability to control the amplitude of a waveform makes them essential components in various electronic systems, ensuring reliable and efficient operation.

Let's explore some of the common applications of clipper circuits:

1. Audio Processing: Clipper circuits are employed in audio processing to control the amplitude of audio signals. By using clipper circuits, engineers can shape the waveform of the audio signal, limiting the peaks to prevent distortion and ensuring that the audio output remains within desired levels.
2. Communication Systems: In communication systems, clipper circuits are used to shape and control the transmitted signals. By clipping the peaks of the waveform, engineers can ensure that the transmitted signal fits within the allocated frequency band and complies with signal standards.
3. Signal Conditioning: Clipper circuits are utilized in signal conditioning applications to modify the shape of signals based on specific requirements. This can include removing unwanted portions of a signal or limiting the amplitude to prevent overloading downstream components.
4. Instrumentation: In instrumentation systems, clipper circuits are used to process and condition signals from sensors and transducers. By adjusting the clipping level, engineers can tailor the waveform to meet the specific requirements of the measurement or monitoring system.
5. Pulse Shaping: Clipper circuits play a role in pulse shaping applications, where precise control over the shape and duration of pulses is essential. They help create well-defined pulse waveforms by removing unwanted portions or limiting amplitudes.
6. Amplitude Modulation (AM): Clipper circuits are employed in amplitude modulation systems to control the peak amplitudes of the modulating signal. This ensures that the modulated signal remains within the linear region of the modulator, preventing distortion in the transmitted signal.
7. Television and Video Processing: Clipper circuits are used in television and video processing to adjust the amplitudes of video signals, ensuring that the output signals comply with broadcasting standards and display devices.
8. Data Communication: In digital data communication, clipper circuits can be used to shape the waveforms of digital signals, ensuring that transitions between binary states occur within specified voltage levels.

Conclusion

Clipper circuits are essential electronic components used in various applications to alter the shape of waveforms by clipping or removing a portion of the input signal. These circuits are commonly used in electronics, telecommunications, and audio systems. In this article, we explored the different types of clipper circuits and their applications. We started with an introduction to clipper circuits, highlighting their purpose in waveform shaping. Next, we discussed the classification of clipper circuits, which can be categorized into two main types: series and shunt clipper circuits. For series clipper circuits, we covered the series positive clipper circuit, which removes the positive portion of the input signal, and the series negative clipper circuit, which removes the negative portion of the input signal.  We also discussed the series positive clipper circuit with bias, which allows for selective clipping based on a predetermined bias voltage. Moving on to shunt clipper circuits, we explored the shunt positive clipper circuit, which removes the positive portion of the input signal, and the shunt negative clipper circuit, which removes the negative portion of the input signal.

Additionally, we discussed the shunt positive clipper circuit with bias, which provides controlled clipping based on a bias voltage. We also touched upon dual clipper circuits, which combine the characteristics of series and shunt clipper circuits to achieve more complex waveform shaping. Finally, we delved into the applications of clipper circuits, which include signal limiting, noise suppression, amplitude modulation, and waveform restoration. In conclusion, clipper circuits play a crucial role in various electronic applications by allowing for precise waveform shaping. Whether it's removing unwanted portions of a signal or controlling the amplitude, clipper circuits offer flexibility and versatility. Understanding the different types of clipper circuits and their applications can greatly enhance the design and functionality of electronic systems.