ROTATIONAL POSITION DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a rotational position detector which does not require accurately magnetizing S-pole and N-pole and arranging on a magnetic disk as before and is obtainable with a cheap cost. SOLUTION: At least one tooth among a plurality of teeth of a gear 32 is made a large size tooth 33. With a first voltage comparator 23 and a second voltage comparator 25, the existence of all teeth of the gear 32 is detected with the second voltage comparator 25. The existence of the large size tooth 33 of the gear 32 is detected with the other second voltage comparator, so that the rotational position of the gear 32 is detected with the one voltage comparator and the reference position of rotation of the gear 32 is detected with the other voltage comparator.