TECH PAGE 2

ELECTRICITY CONTINUED

The first subject i will try to explain is audio amplifiers.

Not so complicated if you follow my steps, first you must understand that an audio amplifier is a device that increases a small signal by a factor that is variable to a large signal that can power a speaker so you can hear the result. Essentially this idea is not complete as there are some audio amplifiers that simply increase the voltage level.

It starts off by realising that the input to this amplifier has to come from somewhere and this is usually from a microphone. This i will call a sound to electric converter (sec).

commonly called a microphone. These work as follows, sound is just air being compressed and decompressed at a particular frequency,thus moving the air from the source to the reciever of the sound wave. In the microphone is a coil of wire immersed in a constant magnetic field, the coil is free to move back and forward. The coil is physically connected to a diaphram that responds to the movement of the air. As the coil moves forward and backward through the magnetic field a voltage is produced across the ends of the coil wires.