This medium wave radio works with any general purpose NPN transistor. The diode must be made of germanium and a coil formed by 50 + 50 turns of wire 26 to 30 on a ferrite rod.
This circuit was taken from a Popular Electronics from the 1990s. The circuit triggers a relay that...
The transformer inf this circuit is a 6 or 9 V unit and diodes 1N4002. The filter capacitor is 2...
This circuit causes a relay to oscillate generating a signal that turns into high voltage in a...