| 摘要 |
A control device for monitoring the proper use of an electrical apparatus (1), especially a copying machine, which is connected to a current source via an electric cable (2a, 2b). The device comprises a current sensor (3), e.g. an induction coil, which upon sensing a flowing current delivers a voltage signal to a voltage detector device (5) adapted to detect a characteristic current variation, ocurring when the apparatus is used, and thereupon deliver an operation indication pulse to a control unit (8), in particular in the form of a computer, which is connected, on the one hand, to an authority check unit (12, 11), through which a user of the apparatus can feed an authorization signal to the control unit, and, on the other hand, to a switch (9) for interrupting the supply current to the apparatus in the absence of said authorization signal. |
