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Calculation of Capacitance.

The following formula is used to calculate the capacitance between rectangular parallel plates
For Semi-circular rotor plates the calculation of the area of the plate uses Half the Width, Not the height.

Capacitance = (0.2248 xKx Eo xA)/din pF
where:- 'd' is the distance between plates, 'k' is the dielectric constant and 'A' is the area of the smaller plate.

Enter Width in inches (smallest plate) inches
width in millimetres mm
 Enter Height in inches (smallest plate) inches
height in millimetres mm
 Enter dielectric constant (see dropdown list above) k
 Enter spacing between plates in inches (1mm=.0394in)  inches
spacing between plates in millimetres mm
 Enter total number of plates (moving & fixed)

Click here for default values

 Capacitance pF
 Area of plate calculated from W & H (Imperial) sq inch
 Area of plate calculated from W & H (Metric) sq cm  
 Select dielectric from list below and re-calculate to find approximate breakdown voltage
Plate radius = Width / 2 = inches radius squared =
Using semi-circular rotor plates, Area = sq in   = sq cm Capacitance = pF
Once you hit Calculate and have a result, you can change any value and Calculate again.
Examples of Non rectangular plates < Back to Calculations >