| 摘要 |
A battery has an exposed negative terminal 2, but the positive terminal 10 is hidden within the casing of the battery, and instead only a dummy terminal 3 is visible. This is connected to the real positive terminal 10 via a normally closed heavy duty switch, such as a solenoid 9. An electronic control board, 8 senses any unauthorised attempt to start the vehicle via voltage changes at terminials 4 or 5 or the volt drop detector 17 in the stand alone version. The resultant change of output voltage from the control board 8, operates the solenoid 9, thus removing the main power available from the battery, and preventing the engine from being started. To prevent radio codes from being lost a small by-pass circuit 14 allows a small amount of current to be drawn from dummy terminal 3. The authorised user has a key fob transmitter which is pressed on approaching the vehicle. A receiver 7 inside the battery receives the signal and inhibits the solenoid 9, so full power is always available until the completion of the journey. When the ignition is then switched off the battery reverts automatically to standby mode after a pre-determined time. |
