This crystal or galena radio is one of the many versions available on this website. This is from a documentation from the 70s. The coil is formed by 50 + 50 turns of wire 28 in a ferrite rod.
This electronic rheostat with SCR was found in the June 1964 Radio Electronics magazine. The SCR...
This circuit consists of a small inverter to light a low voltage neon lamp. The circuit is from a...
Unlike the CIR4620 circuit, the circuit shown in the figure operates by capacitance. This means...