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.
This is the traditional configuration of a differentiator with an operational amplifier. This was...
This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The...
We found this circuit in Motorola's Circuit Applications for the Triac 1971 manual. The circuit is for ½...