Capacitive displacement sensor - QuickField simulation example
Capacitance of a coaxial displacement sensor as the inner cylindrical electrode moves, providing the capacitance-versus-displacement characteristic.
How to calculate the capacitance of a coaxial displacement sensor as the inner electrode moves?
Answer Typical applications Geometry
Given
Task
Solution
Results
Engineering question
Calculate the stored electric-field energy for successive electrode positions and use it to determine the capacitance.
capacitive touch electrodes, touch sensor buttons, human interface sensors
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Simulation problem
Problem Type
Axisymmetric problem electrostatics.
Relative permittivity of air ε = 1.
Calculate the capacitance as a function of the inner cylinder's displacement.
We apply the potential difference of ΔU = 1 V to the cylinders and measure the electric field energy W stored in the air.
The capacitance is 2*W / ΔU ².
A set of QuickField problems with different cylinders position is automatically generated by the Label Mover tool.
At zero displacement the capacitance is 2*7.57e-12 / 1² = 15.14 pF.
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