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 was obtained in an old publication of 1978. The integrated circuit is the critical...
When an alternator is used to supply constant current, it needs an adjustment that must be made as...
This timer, from an old American publication, uses indicator lamps, but can be modified to use...