This is a Class C amplifier. It is used to boost the signal of an audio source, increasing its volume.
A class ab amplifier is an amplifier that has a power class of 0.1 to 100 watts, and an audio frequency response between 20 Hz and 20 kHz.
A Class C amplifier is one of the most efficient amplifiers available. This article will go through the working concept, features, uses, benefits, and drawbacks in depth. Amplifier Classification and Waveform have also been included for a better understanding.
Amplifiers are categorized in a variety of ways based on their design, active device, output, input, coupling technique, frequency range of operation, and, most importantly, biasing conditions or mode of operation.
Linearity, signal gain, efficiency, and power output are the key operational properties of an ideal amplifier. However, there is always a trade-off between these various properties in real-world amplifiers.
Amplifiers are categorized as Class A, Class B, Class AB, and Class C based on their manner of operation. The input signal cycle during which collector current is anticipated to flow determines how amplifiers are classified based on their mode of operation.
Figure 1 shows an analysis of waveforms for several amplifier classes.
Figure 1: Waveform Analysis for Different Amplifier Classes
An Overview of Class C Amplifiers
During the operation of a Class C amplifier, the collector flows for less than half of the AC signal cycle. A class C amplifier has a bias of 80° to 120° for operation for less than 180° of the input signal cycle.
Less than 180° (half cycle) indicates less than 50% and may only be used with a tuned or resonant circuit that operates for the entire cycle of the tuned or resonant frequency.
Class C Amplifier Symbol (Fig. 2)
Because efficiency increases at a large extended level when the conduction angle is decreased, there is a trade-off between efficiency and distortion. However, it causes a great deal of distortion. In RF transmitters, Class C amplifiers typically operate at a single fixed carrier frequency.
The distortion is regulated in these applications by a tuned load on the amplifiers. The active device (transistor) is switched by the input signal, and the current is directed to flow via a tuned load.
Fig. 3: Class C Amplifier Input and Output Waveforms
The Class C Amplifier’s Working Principle
Fig. 4: Class C Power Amplifier Circuit Diagram
Resistor Rb connects to the transistor Q1 base, as illustrated in the circuit diagram above. In the DC load line, a biasing resistor connected to the base of Q1 attempts to pull the transistor’s base further downwards and set the operating pointer dc bias point below the cut-off point (in cutoff, the collector current is ICO, which will be of micro amperes order and thus can be assumed to be zero). The dc load line is the point where the IC and VCE meet and the BJT stays active.
The reason for the absence of the majority of the input signal in the output signal is that the transistor will only begin to conduct after the input signal amplitude has climbed beyond the base emitter voltage (Vbe0.7V), resulting in a downward bias voltage produced by Rb.
Inductor L1 and capacitor C1 create a tuned circuit, also known as a tank circuit, as illustrated in Figure 4. LC circuits are used to generate signals at a certain frequency or to choose a signal at a specific frequency from a more complicated signal by extracting the necessary signal from the transistor’s pulsed output.
The transistor (active element) generates a sequence of current pulses that pass through the resonant circuit in response to the input. By choosing the appropriate values for L and C, the tank circuit oscillates at the frequency of the input signal. The tank circuit attenuates all other frequencies and oscillates at a single frequency.
A properly tuned load is used to achieve the necessary frequency. Additional filters may be used to reduce noise in the output stream. A coupling transformer is used to transmit electricity from the tank circuit to the load.
Characteristics of a Class C Amplifier (Fig. 5)
The operational point in the DC load-line is positioned some distance below the cut-off point, as illustrated in Figure 5, and therefore only a portion of the input waveform is accessible at the output.
Class C Amplifier Applications
The Class C Amplifier is used in the following applications:
- RF oscillators are a kind of radio frequency oscillator.
- Amplifier for radio frequencies.
- Transmitters for FM radio.
- Amplifier boosters.
- Repeaters with a high frequency.
- Amplifiers that have been tuned, and so forth.
Benefits of a Class C Amplifier
The following are the benefits of a Class C amplifier: –
- Increased efficiency.
- In RF applications, the best outcome is achieved.
- The physical size is appropriate for the power level.
Class C Amplifier Disadvantages
The following are the drawbacks of a Class C amplifier: –
- Linearity is a problem.
- This product is not suited for audio applications.
- There is a great deal of noise and RF interference.
- It is very difficult to find perfect inductors and coupling transformers.
- The dynamic range is poor.
Also see: Digital Communication: An Overview, Basic Components, Signal Processing, and Benefits Composition, Types, Properties, and Applications of Ceramic Capacitors
A class c amplifier is a type of electronic device that amplifies the voltage of an electrical signal. The class c amplifier efficiency refers to how much power can be produced by a given amount of electricity.
Frequently Asked Questions
Is there a class C amplifier?
Yes, there is a class C amplifier.
What is the difference between Class A Class B and Class C power amplifier?
Class A amplifiers are the simplest of all and produce a constant voltage. Class B amplifiers produce a constant current, but at a fixed voltage. Class C amplifiers produce a variable current, but at a fixed voltage.
Which class of amplifier has the lowest efficiency?
- class c amplifier uses
- class a amplifier
- class c amplifier circuit diagram
- class c amplifier operation
- class c amplifier advantages and disadvantages