| 摘要 |
PROBLEM TO BE SOLVED: To obtain characteristics which are strong against vibration, impact and the like by adopting patterns and through-conductors placed on circuit boards of a multilayer board as conductors for sensor placed around a current line. SOLUTION: A pattern 7 for sensor is formed on circuit boards 5a and 5b positioned outside a multilayer board 2, respectively. Through-conductors 8 so formed penetrating the circuit boards 5a and 5b are connected with the patterns 7 for sensor. Thus, a conductor 10 for sensor formed in a rectangular pattern by the patterns 7 for sensor and the through-conductors 8 is constituted. The conductor 10 for sensor is so formed that it encircles a current line 6 like a coil, and further is so constituted that the current detection signals 10a obtained from the conductor 10 for sensor are amplified through an amplifier circuit 11. Since the conductor 10 for sensor is thus completely formed on the circuit boards, it is fully resistant with respect to vibration and impact, and the number of parts can be reduced. |
