Types, Classes, Applications of Power Amplifier
An amplifier is an electrical device that increases the magnitude of a signal’s voltage, current, or power. It takes in a weak electrical signal/waveform and, with the help of an external power source, reproduces a stronger waveform at the output.
Amplifiers are categorised as Current, Voltage, or Power amplifiers based on the changes they make to the input signal. We’ll study everything there is to know about power amplifiers in this essay. For additional information on the many types of amplifiers, see the following websites: Amplifiers come in a variety of shapes and sizes, and they’re used for a variety of purposes.
Audio applications, radio communication, medical equipment (MRI), and many more applications employ power amplifiers. So, we’ll study what an Adalm2000 power amplifier is, what sorts of power amplifiers there are, Power Amplifier Classes, and a few uses.
Types of Power Amplifiers
Power amplifiers are classified into three categories based on the sort of output device they are linked to: Audio Power Amplifiers, DC Power Amplifiers and RF Power Amplifiers.
Audio Power Amplifiers
Power amplifiers of this sort are used to boost the amplitude of a weaker audio signal. This category includes amplifiers used in speaker driving circuitries of televisions, mobile phones, and other electronic devices.
An audio power amplifier’s output can range from a few milliwatts (as in headphone amplifiers) to hundreds of watts (as in Hi-Fi/Home theater power amplifiers).
Audio power amplifiers are amplifiers that need amplification in order to amplify audio signals tools. These amplifiers are used in headphones, transmitters, radio equipment, and so forth. For example, if a signal is milliwatts in strength, it may be amplified to thousands of watts.
DC Power Amplifiers
The power of a PWM (Pulse Width Modulated) signal is amplified using DC power amplifiers. They’re employed in electronic control systems that require to operate motors or actuators with high-power signals. They accept input from microcontroller systems, boost the signal’s power, and send it to DC motors or actuators.
The Pulse Width Modulated signals are amplified by these amplifiers. The width of the pulse is modified in this way so that logic signals may be sent to the motors. The input will come from microcontroller units, which will have their power enhanced and will send amplified signals to DC motors.
RF Power Amplifiers
Wireless transmissions need the transfer of modulated waves over large distances through air. Antennas are used to transmit signals, and the range of transmission is determined by the quantity of power delivered to the antenna.
Antennas require input signals with thousands of kilowatts of power for wireless transmissions like FM radio. Radio Frequency Power Amplifiers are used to boost the amplitude of modulated waves’ power to a level that allows them to travel the appropriate distance.
This sort of amplifier is commonly employed in long-distance communications, such as wireless transmissions. Amplification is required for the transmission of such signals so that the signal strength may be increased and the data can be delivered across long distances. These amplifiers are most commonly used for transmitting FM transmissions.
Applications of power amplifiers
The following are some of the applications of power amplifiers in various industries:
Audio power amplifiers are found in practically all consumer electronic products, including microwave ovens, headphones, TVs, mobile phones, and home theater systems, as well as theatrical and concert reinforcement systems.
Industrial: Most industrial actuator systems, such as servos and DC motors, are controlled by switching type power amplifiers.
High-power amplifiers are critical in the transmission of cellular or FM broadcasting signals to subscribers via wireless communication. The use of power amplifiers allows for higher power levels, which boosts data transmission speeds and usability. Satellite communication equipment also uses them.
Classes of Power Amplifier
A power amplifier circuit can be designed in a variety of ways. Each circuit configuration’s functioning and output properties differ from one another.
Power Amplifier Classes are used to distinguish the features and behavior of distinct power amplifier circuits, and letter symbols are allocated to designate the mode of operation.
They are roughly divided into two groups. Power amplifiers for amplification of analog signals are classified as A, B, AB, or C. Power amplifiers that amplify Pulse Width Modulated (PWM) digital signals are classified as D, E, F, and so on.
Audio amplifier circuits employ the most common power amplifiers, which are classified as classes A, B, AB, or C. So, let’s take a closer look at them.
Class A Power Amplifier
Positive highs and negative lows make up analog waveforms. The complete input waveform is employed in the amplification process in this type of amplifier.
Both the positive and negative portions of the waveform are amplified by a single transistor. As a result, class A amplifiers are the most widely utilized form of power amplifier. Despite the fact that superior designs have since replaced this type of power amplifiers, they remain popular among amateurs.
Even though there is no input signal, the active element (the electrical component used for amplifying, which in this example is a transistor) is in operation all of the time in this type of amplifiers. This produces a lot of heat and lowers the efficiency of class A amplifiers to 25% in the standard setup and 50% in the transformer connected design.
Class A amplifiers have a 360° conduction angle (the fraction of the waveform used for amplification out of 360°). As a result, signal distortion levels are minimal, allowing for improved high-frequency performance.
Class B Power Amplifier
Class B power amplifiers are intended to improve the efficiency and eliminate the heating issues that plague class A amplifiers. This type of amplifier uses two complimentary transistors instead of a single transistor to amplify the full waveform.
The positive half of the waveform is amplified by one transistor, while the negative half is amplified by the other. As a result, each active device conducts for one half (180°) of the waveform, and when two of them are coupled, the signal is amplified completely.
Because of the two transistor architecture, class B amplifiers are far more efficient than class A amplifiers. They can theoretically achieve a 75 percent efficiency. This family of power amplifiers is found in battery-operated devices such as FM radios and transistor radios.
Class AB Power Amplifier
Class AB amplifiers combine the best features of class A and B amplifiers. This class of amplifiers is intended to address the inefficiency of class A amplifiers as well as signal distortion at the crossover area of class B amplifiers.
It keeps the high frequency response of class A amplifiers while maintaining the efficiency of class B amplifiers. To create a low bias voltage, a combination of diodes and resistors is utilized, which lowers waveform distortion near the crossover area. As a result, there is a 60 percent reduction in efficiency. Class AB amplifiers are designed to decrease signal distortion. A little distortion exists in the crossover area due to the superposition of two parts of the waveform.
Class C Power Amplifier
Class C power amplifiers have a lower linearity/conduction angle than class A power amplifiers, which is less than 90 degrees. In other words, it makes a trade-off between amplification quality and efficiency.
Because a smaller conduction angle means more distortion, this type of amplifier is not suitable for audio amplification. They’re employed in high-frequency oscillators and radio frequency signal amplification.
Class C amplifiers typically have a tuned load that filters and amplifies input signals of a certain frequency while suppressing waveforms of other frequencies.
Conclusion
In conclusion, Power amplifiers are the most basic type of amplifier, and they are used to increase the power of an input signal, which can be digital or analog, from a few milli watts to several milli watts, depending on the amplification requirement. Amplifiers of this sort may be found in practically every analog to digital gadget in our environment. Power amplifiers are used in everything from radio tuners to microwaves to computers and mobile phones.
Power amplifiers are amplifiers that have the property of transforming the applied DC power from the source into AC power so that the load is provided with adequate power. The magnitude of the applied power tends to rise in this case of amplifiers. As a result, these amplifiers are employed in a variety of applications where power is required to drive a load.
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