Device for measuring the amount of movement of a straightly moving object

摘要

A device for measuring the amount of movement of a straightly moving object is provided with a sensor unit made up of the straightly moving object and stationary members arranged to form two pairs of capacitors therebetween. The confronting surfaces of the moving object and stationary members are graduated with gear-like cuts so that while the capacitances of two of the capacitors are maximum, the capacitance of the other capacitors are minimum. The device further comprises a pair of oscillators coupled to the two pairs of capacitors, and a mixer connected to the oscillators so that the difference in capacitance between the capacitors is obtained as the difference in frequency, which is processed to provide the amount of movement of the moving object.