Vehicle antitheft device operating horn for timed duration - responds to rapid variation in battery voltage to operate relay

摘要

The antitheft device uses an electronic circuit to operate a relay, which operates the vehicle horn, e.g. when an attempt is made to start the vehicle. This circuit comprises a pulse amplifier and a time delay stage, the former triggered by the connection of a load across the battery and the latter causing the circuit output to be reset to its initial state at the end of a given duration, so that the relay is cancelled. This ensures that the vehicle horn is not sounded until the vehicle battery is run-down, the electronic circuit itself having a very small power consumption.