Found in na 1969 Electronics World, this circuit makes use of transistors of the time. Equivalent transistors can be used. The diodes can be 1N4004.
This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times...
This circuit can operate with signals up to 60 MHz using the indicated operational. We found it in...
Activating a relay from pulses (from a monostable, for example) can be useful in many types of...