ABSTRACT
This chapter covers the ac analysis of amplifying devices in response to a sinusoidal signal. Several small signal ac models are used to represent the devices. Hybrid-pi and T-models are two popular ac models used for BJTs and FETs. On the other hand, Thévenin and Norton models are used for triodes. By carrying out the ac analysis with an appropriate ac model, the voltage gain, input and output impedance can be determined for an amplifying device for three basic configurations. The three basic amplifying configurations for BJTs are common emitter, common base, and emitter follower. FETs and triodes also have similar amplifying configurations but with different names. In addition to the ac analysis of single-device amplifiers, some compound amplifiers are also discussed. They include the differential amplifier, follower compound amplifier, SRPP, White cathode follower, and cathode coupled phase splitter.
