| 摘要 |
PROBLEM TO BE SOLVED: To protect a coaxial LAN system from the lightning surge by inserting a varistor between the ground terminal of a coaxial lightning arrester and an external conductor of coaxial cable, and then connecting in parallel a plurality of small size varistors of the particular rating between the center conductor of coaxial cable and an external conductor. SOLUTION: A first lightning element 7-2 is inserted between the ground terminal 7-1 of a coaxial lightning arrester and an external conductor 1-1 of a coaxial cable 1. Moreover, a second lightning element 7-3 is inserted between the center conductor 1-2 and the external conductor 1-1 of the coaxial cable 1. Here, as the first lightning element 7-2, a varistor having the operation start voltage of DC200 V or higher, suppression voltage of 1.5 kV or less and dielectric strength of 1kA or higher for the lightning surge current waveform of 8×20μs is used. Moreover, as the second lightning element 7-3, a small size varistor having the operation start voltage of 10 V or less, static capacitance in the parallel connection of 30 pF or less is used. As a result, the coaxial LAN system can be protected from voltage difference generated by the lightning surge.
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