A simple amplifier

Amplifiers are the basis of many types of electronic circuit. Amplifiersmight refer to the many types of audio amplifier that abound in the home, from the amplifier in the stereo or CD player to those in the video recorder, not forgetting the more humble amplifiers we find in a telephone, a fax machine or a microwave oven (amplifying the “beep”). Then amplification of other types of signal is considered. Cameras, security systems, and dishwashers provide several instances of amplification. But signal amplification is not the only use for an amplifier, for most oscillators include some kind of amplifier. The “beeps” and many other sounds and flashing lights which produce the output of so much domestic and industrial equipment, nearly always depend on an amplifier. So do the oscillators that form part of radio and TV circuits. This chapter begins by looking at an amplifier that is based on a single transistor.