| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent breakage of a two-wire system wiring accessory caused by a short-circuit current. <P>SOLUTION: In a two-wire system wiring accessory, a load opening and closing device 100 with a human detection function is connected to two power supply line connection terminals T1 and T2 for feeding power from a commercial power supply 11. A switching transistor Q1 being turned on and off corresponding to feeding or non-feeding to a load 12 is provided in the load opening and closing device 100 with the human detection function. An instantaneous value of a current flowing in the transistor Q1 is acquired from an output of a comparator CB, and an average value thereof is acquired from an output of a comparator CA, respectively. Control is performed based on the instantaneous value and the average value to make a current resistant amount of the transistor Q1 be within a rated value. Thereby, breakage of the load opening and closing device 100 with the human detection function which is caused by a short-circuit current flowing in the transistor Q1 can be prevented. <P>COPYRIGHT: (C)2012,JPO&INPIT |
