ࡱ> 8:7[  bjbj 4ΐΐ83:G]]]]yyy$@Ry^yy]]y^]]y]P#q04 v4 4 yyyyyyyMyyyyyyy4 yyyyyyyyy : L INTERCOM This is the circuit of a simple intercom for personal conversation between two persons. It is a real fun for the children. Condenser Mic is used to pick up sound signals which are amplified by inverting amplifier made of IC 741. The amplified signals are given to a speaker which gives the audible voice. Capacitors C1 and C3 are DC blocking capacitors. Resistor R1 reduces the current to Mic and determines its sensitivity. Assembling Assemble the circuit on the PCB. Two units are required to make the Intercom. Observe polarity of capacitors, Mic and battery snapper. Orient IC in the correct direction. Connect the two units using two long wires (Thin wires) as shown in the diagram. Wiring Connect the ends of the wires to speaker connection points of PCB1. Connect the other ends to Speaker 2 that is kept in the unit 2. 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