Found in an old publication about neon lamps this circuit works directly connected to the power grid, serving as an indicator for various situations. Ordinary neon lamps can be used.
This circuit has already been presented from other manufacturers' manuals. This one, specifically, is from...
Other settings like this can be found on this website. This makes use of old operational...
This simple 555 component tester was found in the November 1992 issue of Radio Electronics...