| 摘要 |
<p>An electrical indicator or alarm circuit for a vehicle can detect whether a vehicle is connected to alternating mains voltage. To do this there is a control circuit (11), which has an output connection connected to an alarm means (33, 31), and which is also connected to one end of an electrical influence conductor (9). An alternating voltage is induced or formed capacitively in the influence conductor when the vehicle is connected to the electrical mains supply network, by virtue of the fact that the influence conductor lies close to the mains conductor (7) in the vehicle. The influence voltage formed can be detected by the control circuit by virtue of the fact that the other end of the influence conductor is not connected to any electrically conducting component and has high resistance to such electrically conducting components. When the influence voltage is detected, a signal can be provided on a line (13) to a warning light, for example, so that it is turned on. The circuit can also detect whether the vehicle ignition system (29, 32) has been turned on and if this is the case and there is influence voltage at the same time, to trigger an alarm, e.g. an acoustic alarm (31).</p> |
