The indicator for this circuit is a 0 to 1 mA milliammeter. The operational is from the 70s, when the circuit was published. Modern equivalent can be used.
This 1995 circuit uses interruption sensors or NC connected in series in any quantity. With the...
The integrated circuit used in this amplifier is not common today. The circuit is from a...
This circuit turns off a load after an interval of 8 to 80 seconds adjusted on the potentiometer. The...