| 摘要 |
<p>A first embodiment of the present invention has toroidal current transformer 11 having its outputs connected across full-wave bridge rectifier 12. The induced, rectified current produced by full-wave rectifier 12 is converted to a voltage by a load resistor. This voltage is compared to a reference signal, the magnitude of which corresponds to a quiescent current level, by comparator 13. When the load resistor voltage exceeds that of the reference voltage, a current surge is detected. The output of comparator 13 is directed to a retriggerable monostable multivibrator 14 which produces an activation pulse of a selectable and known duration. The activation pulse is directed to an electromagnetic or solid-state relay 16 which activates peripheral device 2 by connecting it to its power supply. The second embodiment of the present invention has line sensor 18 electromagnetically coupled to power supply line 3 the output of current sensor 18 is integrated by integrator 19. The integrated signal is then digitized by digitizer 20 and input into selector 21. A crossover detector 28 and line voltage sensor 25 are operably connected to power supply line 3 to monitor the crossover points and voltage level of the supply. The monitored voltage is digitized by digitizer 27 and input into selector 21. Selector 21 alternatively supplies microcontroller 22 with the digitized line current and voltage level values. Microcontroller 22 compares the relative values of the line current and voltage level to detect current surges in power supply line 3 due to increased activity of parent device 1. Microcontroller 22 then activates solid-state relay 24, thereby activating peripheral device 2.</p> |
