| 摘要 |
PURPOSE:To detect earthing simultaneously with the continuity test for a twisted pair line, by providing an earth detecting part between one terminal of a continuity tester and the earth. CONSTITUTION:A buzzer 1 is connected in series to a DC power source E1, and an electronic buzzer 2 is connected in series to a DC power source E2 and is connected between a terminal Y of the buzzer 1 and the earth. The electronic buzzer 2 changes the tone color in accordance with an applied voltage and is different in tone color from the buzzer 1, and the working current of the electronic buzzer 2 can be set to a value smaller than that of the buzzer 1. When this continuity tester is used and terminals X and Y are connected to terminals A and B to perform the continuity test, the buzzer 1 sounds in case of normality to detect the continuity. If the twisted pair line is connected erroneously to terminals B and B' or is connected normally but is earthed, the electronic buzzer 2 sounds together with the buzzer 1, and thus, the erroneous wiring and the earthing are detected simultaneously. |
