LOW BUDGET INTERCOM

THE central component in this Intercom project is an integrated circuit designed for audio amplification, type LM386. It is shown as IC1 in Fig.4.3. The circuit shows that it needs few additional components to do its job of amplifying audio signals. The internal voltage gain is set at 200 by capacitor C2, connected between
pins 1 and 8. Two low-power loudspeakers, LS1 and LS2, act as microphone or speaker depending on the position of the double-pole, double-throw reversing switch, S2.

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Everyday Practical Electronics, January 2009