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.
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...
This circuit is from a 1966 General Electric documentation. The circuit applies to sensitive SCRs for...
This circuit consists in a capacitor bridge for capacitance measurements. The circuit can be...