Found in the September 1982 issue of Radio Electronics magazine, this circuit triggers a relay intermittently. Triggering is done by a reed switch, but other types of sensors can be used.
This circuit was found in a 90s Popular Electronics. The components are from the era. R3 must be...
This circuit is from the magazine La Radio per Tutti of 1926. The primary and secondary coil have...
The sensor for this circuit, found in a 1992 publication, is a phototransistor. The power is...