We found this circuit that triggers an SCR in the Encyclopedia of Electronic Circuits volume 5 of 1995. The circuit is powered by voltage according to the warning load.
This low-power circuit for small lamps according to transistors was found in the January 1959...
This dimmer for the 120 V (117 V) network was found in the magazine Electronics Now of August...
This old amplifier uses germanium transistors from the time. The circuit is from a Mullard...