The gain of an amplifier can be stabilised and the internally generated distortion reduced by introducing negative feedback. This can be applied from the output to input of a single stage or alternatively over several stages. With single stage common-emitter amplifiers, negative feedback can be obtained in two ways; by feedback from collector to base (Fig. 19.4) via RF, or by including an unbypassed resistor RE in the emitter circuit. The latter is very useful and is commonly used.
Fig 19.3 Tone control