The circuit is from the MC1539 manual, an operational one close to the 741. The transistor admits equivalent and must be mounted in a good heat sink.
This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times...
We find the original version of this circuit in an English publication (1986). It is a...
In the figure we have the way to implement a logic gate or (OR) with an LM393. The circuit must be...