Automotive alarm schematics

Like the first two Hijack Alarms - if a door is opened while the ignition is switched on - the circuit will trip. And after a few minutes delay - when the thief is at a safe distance - the Siren will sound. But this time the engine does not go on to fail automatically. Instead - it will continue to run until the thief turns off the ignition. Then the engine will not re-start.... [read more]

This car alarm circuit features Exit and Entry delays, an instant alarm zone, an intermittent siren output and automatic Reset. By adding external relays you can immobilize the vehicle and flash the lights.... [read more]