Intercom Circuit Diagrams
Intercom Circuit Diagrams
This intercom uses an ordinary speaker to function as its microphone. Once the button is pressed, the relay toggles, and the speakers interchange their functions.
One works as a normal speaker and the other one works as microphone.
The circuit is composed of a complementary final amplifier (T3 & T4) and two voltage preamplifiers (T1 & T2). Pot P1 controls the volume.
The voltage at the common junction of resistors R5, R6 & P2 must be set to one half of the supply voltage.
A lower impedance speaker with a series resistor can replace the suggested type, but will deliver lower sound quality.
 |
| Intercom Circuit Diagrams |
Intercom Circuit Diagrams
This intercom uses an ordinary speaker to function as its microphone. Once the button is pressed, the relay toggles, and the speakers interchange their functions.
One works as a normal speaker and the other one works as microphone.
The circuit is composed of a complementary final amplifier (T3 & T4) and two voltage preamplifiers (T1 & T2). Pot P1 controls the volume.
The voltage at the common junction of resistors R5, R6 & P2 must be set to one half of the supply voltage.
A lower impedance speaker with a series resistor can replace the suggested type, but will deliver lower sound quality.