and second as microphone. The 10K variable resistor is used to adjust the volume and 5K variable resistor between the pin 1 and 8 is used to adjust the gain. For switch use DPDT push switches on the both sides. Also include the power on off connection with in the DPDT push switch it will save the battery connected to the circuit all the time and the battery will only connect to the circuit when some one push the switch for talking. Use 9V battery or 9V power supply with the circuit.
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