We found this circuit in the May 1990 issue of Radio Electronics magazine. The circuit is powered by the relay used and uses both normally open and normally closed sensors.
Found in an English documentation from 1989, this circuit uses components common today. The...
The LED frequency flashes depends on the value of the capacitor tested according to the table. We...
Found in a Popular Electronics from the 90s, this circuit generates a signal that depends on the...