An audio amplifier is an electronic device that increases the power of audio signals. It takes a weak audio signal, such as from a microphone or musical instrument, and boosts it so that it can drive speakers or headphones, producing louder sound. Amplifiers are essential in various audio systems, including home theaters, public address systems, and musical performances. There are different types of audio amplifiers, including class A, class B, and class D, each with unique characteristics and efficiencies. The choice of amplifier can affect sound quality, power consumption, and overall performance of the audio system. Understanding these differences helps users select the right amplifier for their needs.