On the Indexing Accuracy of Gear Type Condenser

Fig. 1 (a) shows a gear type condenser consisting of an internal gear and an external gear, both of which have the same module, pressure angle, and number of teeth. The internal and external gears can move around the same axis, but are electrically insulated each other. This pair of gears then turns to be an electric condenser of which capacity is uniquely defined by the relative position between two gears. The gear type condenser can give a precise measurement of small angular displacement. The sensitivity is about 1 volt for 1 second. However in this paper will be discussed another way of case of this condenser e. the accurate way of indexing. The internal and external gears used in the gear type condenser may have a pitch error. However it is quit e possible to make a very accurate division of 360°(indexing) by the number of teeth with this condenser. The error for indexing does not depend upon a pitch error of gears used in condenser.