This two-port monostable of the 4001 was suggested by an article in the April 1988 Radio Electronics magazine. The timings are given by C1 and R1.
This circuit uses common components activating a control relay for the water pumps. The sensors are...
This circuit is from a publication from the 70s. The operational amplifier is from the period. Modern...
The LM121 integrated circuit is no longer common in our market, with more modern equivalent...