This transistorized siren was found in the patent section of Radio Electronics magazine from March 1968. The circuit uses components from the time and has a very elaborate configuration.
This circuit from the April 1972 issue of Radio Electronics magazine uses an inductive sensor. The...
This circuit can either generate signals in the astable form or be synchronized externally,...
The purpose of this circuit is to improve a trigger circuit using a zener diode. The circuit was...