Variable capacitor - QuickField simulation example
Mutual capacitance between the two stators of a variable air capacitor versus rotor position, showing how plate overlap controls capacitance.
How to find capacitance versus rotor position in variable air capacitor?
Answer Typical applications Geometry 3D extrusion.
Given
Task
Solution
ResultsEngineering question
Calculate stored electrostatic energy at each rotor position and obtain capacitance from C = 2W/U^2.
variable air capacitors, tuning capacitors, rotor-stator plate capacitors
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Simulation problem
Problem Type electrostatics.
Relative permittivity of air ε = 1,
Potential difference ΔU = 1000 V
Find the mutual capacitance between two stators as a function of the rotor position.
QuickField simulation gives energy W and electric potential U distribution. The capacitance then can be calculated as C = 2W / ΔU².
Rotating angle α
Energy W
Capacitance C
0°
1.29 uJ
2.58 pC
30°
2.25 uJ
4.50 pC
60°
2.97 uJ
5.94 pC
90°
3.22 uJ
6.44 pC
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