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 originally recommended to operate with the emitter of the previous circuit but...
We found this circuit in the 1989 Radio Electronics Experimenter. The circuit uses common...
The power supply shown in the figure provides voltages between 0 and approximately 15 volts, with...