The principle of operation used in capacitive transducers to measure level of liquid is change of

Capacitive transducers:

• A capacitor consists of two conductors (plates) that are electrically isolated from one another by a non-conductor (dielectric).
• When the two conductors are at different potentials (voltages), the system is capable of storing an electric charge.
• The principle of operation of capacitive transducers is based upon the equation for the capacitance of a parallel plate capacitor.

\(C = \frac{{\varepsilon A}}{d}\)

Where A = overlapping area of plates in m2,

d = distance between two plates in m,

ε = permittivity (dielectric constant) in F/m.

• The capacitive transducers work on the principle of change in the capacitance of the capacitor.
• This change in capacitance could be caused by a change in the overlapping area of the plates, change in the distance between the plates, and change in dielectric constant.
• In most of the cases, the above changes are caused by the physical variables, such as displacement, force, or pressure.
• Variation in capacitance is also there when the dielectric medium between the plate’s changes, as in the case of measurement of liquid or gas levels.