AC Power Amplifiers

Alternating current (AC) power amplifiers are electronic devices that take AC input signals and increase their amplitudes. Power can be calculated using the following equation, where “V” is equal to voltage measured in volts and “I” is the current measured in amperes (amps).


AC power amplifiers can amplify the power in terms of voltage, current, or both. They can be designed to be voltage amplifiers (outputs a changing voltage signal with respect to a changing input voltage signal) or transconductance amplifiers (outputs a changing current signal with respect to a changing input voltage signal). The key specifications that determine the performance of an amplifier are: gain (ratio between output and input signal amplitudes), bandwidth (effective frequency range), regulation (change in the output due to variations in the load and the line voltage), efficiency (ratio between output power and total power consumed), linearity (how similar the output waveform is compared to the input waveform) and total harmonic distortion (amount of distortion in output due to circuit nonlinearities and noise).

Application of Power Amplifiers

The most common home application of AC power amplifiers is amplifying audio signals (audio power amplifier). Audio power amplifiers amplify low power audio signals to drive loudspeakers. The most important qualities of audio power amplifiers would be their frequency response to be within the audible frequency range (20 Hz – 20K Hz), the gain and the amount of total harmonic distortion. The typical audible frequency range of the average human being is about 50 Hz – 16K Hz.

Industrial grade AC power amplifiers are made with variations in their design qualities for specific applications. Industrial and scientific applications of AC power amplifiers include plasma excitation, induction heating, EMC testing, EMI testing, magnetic field generation, medical research and testing products such as piezo elements, inductors, capacitors, transformers, Helmholtz coils etc.

The main difference between audio power amplifiers and industrial grade power amplifiers is that industrial grade amplifiers are manufactured to handle extended periods of continuous duty. Audio power amplifiers are rated for peak power while industrial power amplifiers are rated for continuous power. Industrial power amplifiers can have frequency responses covering, within or outside the audio frequency range.  Ultrasonic frequencies power amplifiers and radio frequency (RF) power amplifiers are highly used industrial power amplifiers.

Amp-Line Corp.

Amp-Line Corp. manufactures wideband linear AC power amplifiers built for a variety of industrial and scientific research applications. They vary from output power levels of 50 W to 1400 W with bandwidth covering the entire audio frequency range as well as part of the ultrasound and radio frequency ranges (up to 800K Hz). Contact the technical department of Amp-Line with your specific wideband AC power requirements.

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