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 conventional version with a transistor, already explored many times on our website, was found...
This circuit came out in an English magazine from 1977, but it can be easily assembled today, as...
This simple radio for listening to a headphone with two CK722 transistors was found in Radio...