Two sensors are used in this simple remote-control circuit, one to switch on and one to switch off the relay. The circuit is from 1986 documentation. The transformer has 12 V of secondary.
With a 1 500 uFcapacitor this timer can reach times up to one hour. The capacitor must be of good...
We found this circuit in a 1975 filter cookbook. The circuit can use other operational amplifiers and...
This circuit is from an Italian publication from 1988 but can still be easily assembled....