| 摘要 |
A passive vehicle antitheft system utilizes a unique combination of condition responsive switching components to control the access to and use of a vehicle. Primary control over the vehicle is provided by a control relay including a first "protection" position in which the vehicle ignition system and starter are disabled and an alarm system is enabled and a second "use" position in which the ignition system and starter are enabled and the alarm system is disabled. The control relay is in turn controlled by three bistable switching components that are selectively enabled and disabled at various stages of use of the vehicle. The switching components, which in the preferred embodiment comprise a triac, a silicon controlled rectifier, and a second relay, automatically switch the control relay to its "protection" position as an authorized user leaves the vehicle and closes the last vehicle door. The switching components are also interconnected and arranged to provide protection against attempts to tamper with or defeat the system. |
