Below is a schematic diagram of a lm386 circuit / lm386 amp which can be used as a simple audio amplifer to increase the audio of your radio, mp3 players etc. The circuit is using lm386 amplifier IC, maximum gain of the circuit can be set between 20 to 200, the 10uF capacitor from pin 1
to 8 is used to set the gain of 200. If you want gain of 20 then remove the 10uF capacitor from pin 1 to 8. This lm386 circuit will work on 9 volt or 12 volt from any source like adaptor or battery.