This car alarm was obtained in a Signetics documentation from the 1980s. The circuit uses the 555 and has a pulsed output to activate a relay that controls the horn. The sensors are parallel connected.
This traditional mixer configuration with a high input impedance was found in a 90’s Popular...
This 1989 documentation circuit uses a digital display with components that are uncommon today,...
This conventional H-bridge current monitor circuit was obtained from a 2005 Linear Technology...