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.
Originally this piezoelectric microphone preamp was designed to be built-in, but given the use of a...
This is the traditional configuration of Baxandall bass and treble control, using passive...
We found this circuit in an American publication from the 1990s. The triac must be equipped with a heat...