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.
The operational amplifier used in this configuration is uncommon today, but more modern types can...
This circuit triggers some load such as a lamp, video camera and monitor when someone rings the...
This circuit can keep a set of lamps on for up to 1 minute, time given by C2 and R2 that can be...