Class B Amplifiers

Class B amplifiers are essentially the opposite of those that operate in Class A. No current flows when the output devices are idle, and thus must turn on from a zero-current state when signal is present. In addition, both output devices (negative and positive) are never active at the same time. If given a sine wave, each output device will operate for half the waveform. Thus, Class B amplifiers are very efficient; however, the linearity of the amplifier suffers when the signal approaches the point at which the output devices change. Class B operation amplifiers are not generally used for professional audio equipment, and are reserved for low-power operations such as radios.