What is Power Amplifier ?

Power Amplifier
Power Amplifiers are very simple devices in concept. They take a small signal and increase its power so that a loudspeaker may be connected to its output terminals. Home theater power amplifiers come in many configurations and power ranges. In any system one amplifier "channel" is needed for each speaker in your home theater system. (Note: Some sub-woofers include their own internal power amplifier so you might only require five channels of amplification). Some power amplifiers combine all five or six amplifiers in a single chassis, others, which are sometimes called "mono blocks," will only power a single loudspeaker. How much power do I need? The answer to that question is not simple. It is a complex relationship between the size of your room, the efficiency of your speakers, and ultimately your individual requirements for volume or sound pressure level (SPL). Generally amplifier power outputs of less than 50 watts per channel are considered "low," 50 to 100 watts "medium," and over 100 watts "high."