Driving method of crossed coil type meter

Abstract

Abstract PURPOSE:To improve the linearity of the indication degree of a crossed coil type meter on the basis of trapezoidal wave driving signal by using two driving signals different in phase changed by the characteristics of an isosceles trapezoidal in which the ratio of the lower bottom to the upper bottom is about 2.29. CONSTITUTION:A movable magnet 3 magnetized to two poles is positioned in an inner space of a pair of coils 1, 2 arranged so that their mechanically crossed angle is 90 deg.. A pointer 5 is fitted to the point of a pointer shaft 4 expanded from the center part of the movable magnet 3. Driving signal generating circuits 6, 7 different in phase corresponding to 90 deg. electric angle and generate driving signals 6a, 7a to be alternately changed by the characteristics of the isosceles trapezoidal in which the ratio of the lower bottom to the upper bottom is about 2.29. The driving signals 6a, 7a having different phases are constituted so as to advance their phases in accordance with the increment of the measured values such as a car speed and the rotational frequency of an engine.

Inventors

• 👤 Etsuo Ichimura
• 👤 市村　悦男

Bibliographic Details