This circuit was found in the July 1986 issue of Radio Electronics magazine. The circuit has a loudspeaker warning system. The sensor is the ceramic capacitor C1 which acts as a transmission line.
In the figure we show how to trigger a triac for a continuous voltage of the order of 2 V,...
This 2005 Linear Technology circuit has separate outputs for monitoring the charge and discharge...
This circuit was obtained in a June 1987 magazine Hands-On. It is a circuit that indicates on two...