We found this circuit in the 1983 Radio Electronics Special projects magazine. The components are common, and the circuit drives a relay. The power supply must be isolated.
We found this circuit in a Popular Electronics of the 90s. The circuit still uses light bulbs, but...
This circuit is from Linear Technology 2005 documentation. The circuit is based on company...
The integrated circuit used in this power supply is no longer very common in power supplies today....