This circuit was found in a Popular Electronics from the 90s. It is intended to power the filament of old radio valves in recovery works. It is indicated for tubes that use 5 V of filament.
Found in a 90s Popular Electronics, this simple circuit turns on a light when the light stops to...
This circuit was published in an English magazine from 1980. The magazine no longer exists, but...
This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are...