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Views: 5 Author: Site Editor Publish Time: 2023-03-08 Origin: Site
Power amplifiers are used to increase the power level of a signal. These are essential components for many electronic applications such as radar, avionics, communications, satellite imaging, heating, microwave imaging and implantable devices.
In general, power amplifiers are divided into three classes: class A, B and C. These classes are characterized by their efficiency, linearity and conduction angle. The lower the efficiency of a class A amplifier, the higher its signal distortion.
A Class B amplifier has lower efficiency than a Class A amplifier but greater linearity range. It also has a higher conduction angle than a Class A amplifier. It is most suitable for audio amplification because it can achieve high power output with a low noise level.
This is because the class B amplifier is able to control the load resistance of the fundamental transistor very well and generate a sinusoidal voltage waveform. The second-harmonic impedance remains in the negative resistance region at a very high power level.
The main disadvantage of this amplifier is that the circuitry is complex and needs high precision. This makes it unsuitable for mass production.
Digital power amplifier is a modern type of amplification that uses pulse width modulation and a high quality switching output stage to provide a true digital i2S (i.e. a SPDIF) input. This eliminates the extra steps of a traditional D/A and A/D conversion process, resulting in very low HF and audio frequency noise.
In addition to its superior performance, this amplifier has two built in fans that help keep it cool and working at optimum level. It also has a digital link output so the pre amp audio can jump to other power amplifiers, which is important for a multi-channel speaker system.
A power amplifier converts a low-power signal to a high-power one. A power amplifier can be used to drive loudspeakers, headphones or wireless communication equipment, such as cellular phones or microwave ovens.
A professional amplifier is a power amp designed for commercial and professional use in audio, home theatre or home entertainment systems. It can be a single-channel unit or a multi-channel amplifier. Pro models are designed to be durable and offer more options for audio than consumer amplifiers.
The main difference between a professional and a consumer model is the maximum power that each can deliver at a given time. A consumer amplifier may only have a few hundred watts of power, whereas a pro model could deliver up to four kW for sound reinforcement.
Power amplifiers are classified based on their conduction angle, which is the number of degrees in a cycle during which the amplifying device conducts. The current at the collector flows every time in Class A, half of the time in Class B and less than half of the time in Class C power amplifiers.
A class D amplifier, which has the highest efficiency of all amplifier classes, uses onboard circuitry to create very high-frequency (often over 100K Hz) pulses of DC current. These pulses are then run through the amplifying output transistors, delivering a very powerful amplifier. However, most audiophiles will not use a class D amplifier in their system because they believe that the onboard filtering circuitry is not effective enough to prevent distortion generated by these high-frequency pulses.
Digital audio power amplifier is the newest generation of high-fidelity devices. They offer several advantages over traditional analog-based circuits, including fine detail, noise immunity, high efficiency and configurability.
Digital amplification employs pulse width modulation (PWM), which compares an input signal to a triangular or ramping waveform that runs at a fixed carrier frequency. The duty ratio of each pulse is proportional to the amplitude of the signal, resulting in an accurate and efficient method of representing the signal.
Analog power amplifiers are susceptible to transient intermodulation distortion, which occurs when the output signal is compared with the input signal at very high speeds, such as the speed of sound. Digital power amplifiers do not use any analog amplifier feedback circuit in their power conversion, which avoids this problem.
The overload capability of a digital power amplifier is much higher than that of an analog power amplifier. When the digital power amplifier is overloaded, its output voltage rises rapidly, which can lead to damaging harmonic distortion and rapid sound quality deterioration.
Digital audio power amplifiers use advanced circuit design and spread spectrum technology to minimize EMI interference, which is a major problem for analog-based circuits. Moreover, they are highly suitable for mass production. They can also work without debugging, and they are more stable and reliable than analog circuits. These characteristics make them a popular choice for audio products. Besides, they can be used for low-power, high-efficiency systems with minimal noise and vibration, such as mobile audio, portable media and in-car infotainment systems.
