Found in 1965 Radio Shack documentation, this circuit has a crystal phone output in the 14.8 kHz range. The coil consists of 200 turns of wire 25 in a 1.5 m side square.
This circuit can be used in a differential metal detector to receive the signal from a...
This circuit uses a sensitive reed relay to control external loads. The time delay is given by the...
This amplifier, with a power that reaches 3 W, according to the power that can be from 9 to 14 V,...