We found this circuit in a 1996 publication. The circuit uses components that are still common. The timing depends on C1, which can be changed, and the triac can be of any type.
This circuit applies to other operational ones, other than the one indicated. The formulas next to the...
This circuit can source 3 to 12 V with currents up to 500 mA depending only on the transformer....
This relay circuit is intended for reversing small DC motors. The circuit is from an old...