This circuit was found in a 1966 General Electric documentation. It makes use of direct contact water sensors and therefore requires an isolation or low voltage relay drive transformer.
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...