This timer for long time intervals is from the 1990 Motorola Linear Databook. The setting applies to other operational ones and component values are given below the diagram.
We found this circuit in a 1990 documentation. The operational amplifiers are type 741 and the LED is...
This circuit was found in a 1968’s publication and uses germanium transistors. Equivalents can be...
This 5 V circuit was found in December 1978 Radio Electronics magazine. The power transistor must...