The Study of a Particular Type of Capacitive Transducer for Large Displacement Measurement

The displacement measurement of capacitive transducers of both variable square types and variable clearance types is generally limited in a range of several millimeters to several centimeters. For the measurement of large displacement over 100mm, mainly the measuring devices such as inductorsyn and optical grating are used. It is difficult to use such measuring systems widely for the reason that they have a complex electronic circuit of high cost and high consumption of energy, and it is difficult to integrate the circuit. However, a particular type of capacitive device for large displacement measurement has found its wide application. It is very convenient to apply it widely to both a digital electronic caliper and the displacement measurement of a machine because it eliminates the drawbacks of the aforementioned systems. The paper simply describes the principle of the new capacitive transducer and its measuring system. The error sources of the system are discussed and the methods to reduce it or to improve the measurement accuracy are presented. The result of the experiment is the same as that of the theoretical analysis