Thermal and power considerations in class B transistorized amplifiers

Output power of a Class B transistorized amplifier, driving a complex load impedance, as limited by maximum junction temperature, is discussed. Peak instantaneous power dissipation and the maximum average power dissipation are studied as functions of power factor and drive level. The peak instantaneous power dissipation is investigated, in conjunction with thermal limitations, to derive a design criterion for low-frequency power limit. To give complete consideration to Class B dissipation, a discussion of line voltage variations and quiescent current magnitude is included.