A power amplifier is an electronic device used to increase the magnitude of power of an input signal. Power amps receive a weaker electrical signal and output a corresponding stronger signal using an external power source. Power amplifiers come in different types including the class a amplifier, AB amplifier and class d amplifier.
Although there are several types, classes, models and ratings of a power amp, they all operate under the same principles. Popular types include the adcom gfa 555 and crown xls 100 which both operate by increasing the magnitude of power of an input signal. This power of the signal is increased to a specific level enough to drive the desired loads of output.
A power amplifier drives loads directly, therefore, it is used as a final block in an amplifier chain compared to voltage and current amplifiers. The output is according to its rating, hence a 1000w amp will give that corresponding output.
Input signals to power amps need to be above a specific threshold, therefore, it pre-amplifies input signals. This is done using a voltage/current amplifier before passing the signal to the power amplifier after other necessary modifications.
Mostly found in speakers and TVs, audio power amplifiers are used to increase the magnitude of power of a weak audio signal. The output of these amplifiers ranges from a few milliwatts in headset amps to thousands of watts in large speakers. Common examples of audio amplifiers are the subwoofer built in amps like the parasound amplifier and crown amp.
This amp works with wirelessly transmitted waves sent over long distances via antennas. For transmissions like FM broadcasting, antennas may require inputs of thousands of watts. This requires corresponding high-capacity power amplifiers of up to 2500 watt amps rating or more. Radiofrequency power amplifiers are used to increase the magnitude of the power of the modulated waves for it to successfully travel the required transmission distance.
These types of amps are used to amplify the power of Pulse Width Modulated (PWM) Signals. DC power amplifiers are employed in electronic control systems that need high-power signals to drive actuators or motors. Input is usually supplied from microcontroller systems, its power is increased and fed to the motors.
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