| 摘要 |
This invention relates to a method and device for detecting and indicating the unauthorized entry into an automobile, the unauthorized use of an automobile, and/or the unauthorized removal of an accessory of an automobile. In this invention, a voltage sensing device designed to operate only when the rate-of-change of a potential being sensed is greater than a predetermined value such as would occur when a resistive load is connected across the terminals of a battery. The rate-of-change voltage sensing device is coupled to monitor the voltage from the battery of a car. The rate-of-change voltage sensing device is not sensitive to and does not indicate the mere physical phenomena of a reduction in the battery terminal voltage. An inductive load such as motor or a coil, while it does result in a drop of battery terminal voltage, does not produce a pulse signal having a substantial rate-of-change and, therefore, will not initiate activation of the voltage sensing device. Thus, the voltage sensing device, when connected to a car battery, is selectively sensitive to the coupling of resistive loads to the battery, and insensitive to the operation of a normally operating accessory such as an electric clock. |
