Anti-theft security circuit for vehicle

摘要

The security system has a coded circuit (20) which is activated by a security key, a transponder sent signal or by a code card. The circuit operates separate relays (3, 4, 5) to control the individual circuits which are immobilised by the security system. The power contacts (9, 10) to the security circuit are also linked via decoupling diodes (25, 26) to respective power feeds (14, 17) in some of the protected circuits. The power feeds can be linked to all the protected circuits by individual Graetz rectifier networks while the input feeds to the security circuit can be diode decoupled by separate diodes or by a Graetz rectifier network. With the added power feeds for the security circuit it is impossible to isolate the security circuit by severing its power feeds without totally immobilising the vehicle.