| 摘要 |
PROBLEM TO BE SOLVED: To provide an abnormality detection circuit for a surge protection element for communication capable of easily detecting abnormality such as deterioration for a plurality of surge protection elements with a simple circuit configuration.SOLUTION: A surge protection circuit for communication 100 is configured by: connecting both ends of a surge protection element 101 to the output side of a diode bridge whose input side is connected to a pair of communication lines; connecting one end of the surge protection element 101 to a cathode of a diode whose anode is connected to a ground terminal E; and connecting the other end of the surge protection element 101 to an anode of a diode whose cathode is connected to the ground terminal E. Application of DC power supply voltage to the surge protection element 101 makes a thyristor TH be turned on by leakage current flowing in the surge protection element 101, which makes a light-emitting diode D10 perform display of abnormality. Thereby, deterioration or the like of a plurality of surge protection elements 101 is detected easily with a simple circuit configuration. |
