This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are common neon and the circuit indicates whether the voltage is 110 V or 220 V.
This circuit uses one of the first comercial transistor and is from a 1958’s magazine. Tone...
This circuit is intended to indicate the operation of transmitters with powers above 5 W. The...
Emitt This crystal-controlled oscillator can generate signals from 100 kHz to over 30MHz. The...