ABSTRACT

Many different types of amplifier are found in electronic circuits. Before we explain the operation of transistor amplifiers in detail, we shall briefly describe the main types of amplifier. a.c. coupled amplifiers

In a.c. coupled amplifiers, stages are coupled together in such a way that d.c. levels are isolated and only the a.c. components of a signal are transferred from stage to stage. d.c. coupled amplifiers

In d.c. (or direct) coupled amplifiers, stages are coupled together in such a way that stages are not isolated to d.c. potentials. Both a.c. and d.c. signal components are transferred from stage to stage. Large-signal amplifiers

Large-signal amplifiers are designed to cater for appreciable voltage and/or current levels (typically from 1V to 100 V or more). Small-signal amplifiers

Small-signal amplifiers are designed to cater for low-level signals (normally less than 1V and often much smaller). Small-signal amplifiers have to be specially designed to combat the effects of noise.