We found this circuit in the November 1974 Radio Electronics magazine. The capacitors determine the output time, and it is normal to obtain 1 second for each uF used.
We can use high value electrolytic capacitors in alternating current circuits with the...
Using only one integrated circuit this control was found in an 80's Electronic Engineering. The circuit...
This source of constant current was obtained in an American documentation of 1973. The transistors can be...