This circuit makes use of a low impedance microphone. The relay is according to the supply voltage which can be between 9 and 15 V. The operational gain is approximately 100.
In the figure we have the amplifier application in a NOR gate, with reference voltage equal to the...
Found in 1965 Radio Shack documentation, this circuit has a crystal phone output in the 14.8 kHz...
This oscillator or clock generator generates rectangular signals and frequencies up to 100 kHz....