This circuit of the 80s makes use of an operational one of the time. It can be designed with modern operationals and must use a symmetrical power supply.
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...