These types of transducers are used to measure small displacements. Normally there are two types of Displacement Transducers: contact and noncontact types. Besides the measurement principles can be classified into two categories: electrical sensing and optical sensing. In electrical sensing, passive electrical sensors are used variation of either inductance or capacitance with displacement is measured.
On the other hand the optical method mainly works on the principle of intensity variation of light with distance. Interferometric technique is also used for measurement of very small displacement in order of nanometers. But this technique is more suitable for laboratory purpose, not very useful for industrial applications.
Here I am explaining about contact type displacement measuring equipments.
The commonly used types are:
- Rotary Type Capacitive transducer
- Linear Type Capacitive Transducer