Feed line switching circuit and branching unit

摘要

A feed line switching circuit includes a relay connected between feed lines, a normally close contact of the relay, and a resistor that constitutes a series circuit with the normally close contact, which series circuit is connected in parallel with the relay. The resistance of the coil of the relay and the resistance of the resistor are determined to satisfy the condition that the current flowing through the relay after energizing the relay can prevent the chattering of the relay. Thus, the feed line switching circuit can positively carry out the feed line switching.