Rotational angle detector

摘要

A rotational angle detector for detecting the rotational angle of the rotor in a wide range without requiring dark current. A first detection gear (11) including an m number of teeth and a second detection gear (12) including an L number of teeth are each engaged with a main gear (10) rotated integrally with a steering shaft (1) which includes an n number of teeth. A microcomputer (31) calculates a rotational angle ¸ of the steering shaft using a rotational angle ± of the first detection gear within one cycle and a rotational angle ² of the second detection gear within one cycle.