A Class A amplifier is a type of electronic amplifier known for its high fidelity and linearity. It operates by allowing the output transistors to conduct for the entire cycle of the input signal, which means they are always on. This results in minimal distortion and excellent sound quality, making Class A amplifiers popular in high-end audio applications. However, Class A amplifiers are not very efficient, as they generate a lot of heat and consume more power compared to other amplifier classes. This inefficiency can lead to larger, heavier designs, which may not be suitable for all applications, especially where space and power consumption are concerns.