hello there... in past year. i made intercom from ic LM386 and tr c828. i was happy that day :-). you can buy PCB at store and the schematic too.
You do not need a transistor preamp. The LM386 has a gain of 200 if you add a single capacitor to its circuit as shown in its datasheet. Then it has plenty of gain to amplify a microphone. Each end needs a double throw "push-to-talk" switch that connects their speaker to the wires at rest and disconnects their speaker from the wires and connects their amplifier output instead when they push the switch.
With the speakers connected together at rest, I wonder if one speaker will be a microphone and the other speaker might produce a low sound if a person is screaming at the other speaker??
INTERCOM SET
Posted - Sep 29 2009 : 12:48:14 PM
