This circuit from a Radio Electronics from October 1965 shows how to obtain the action of an SCR when triggering a relay using two transistors. The relay is according to the circuit supply voltage.
This circuit for timing small loads was found in a 1964 General Electric documentation....
Instead of LED bulbs, LEDs with a series 470 ohm 1k resistor can be used in this 80's circuit....
We found this circuit in an English publication from the 1980s. The circuit uses current...