Capacitance measurement

Si-Plan has extensive experience in manufacturing transducers. One of the technologies which can be used in producing a transducer is capacitance measurement. Two distinct forms are employed.

Over lapping plates

Usually used where longer stroke transducers are required, particularly when working within a small diameter envelope. In this situation the principle that the capacitance is proportional to the area of the (overlapping) plates is exploited. Si-Plan has a number of designs which work using this principle.

Parallel plate

In this situation the principle of capacitance varying proportional to the inverse of the distance between the plates is exploited.  Using this technique measurement ranges as low as 60 microns with resolution of a faction of a micron can be achieved, perfect as a sensing element for a load cell, torque cell, extensometer or pressure transducer.  A circuit employing this principle is used in the Si-Plan high temperature extensometer.  Similarly ranges of up to 1M can be achieved for sensing the presence of objects.

Si-Plan has a capacitance measuring sensing element with high level output built into a double sided ceramic hybrid assembly which can be incorporated into a mechanical element to produce a transducer.