Found in a Popular Electronics from the 80's, this circuit makes use of a time integrated to control a relay in a timed way. R2 determines the activation time.
This circuit was found in the June 1978 issue of Radio Electronics magazine. The circuit is...
The slope of an object causes the sensor, a mercury switch to be triggered. The circuit activates...
This circuit for the logic control of the 555 in a power supply was found in the October 1989...