Table of Contents

General Equations

See also: General constants

Capacitance

General note: \epsilon_r is the dielectric constant of water, where \epsilon_0 is the dielectric constant of free space. See the General Constants page for values. All length/radius/area values are in meters.

Parallel Plates

Area A in square meters. d is the distance between plates

C = \frac{\epsilon_0 \epsilon_r A}{d}

Concentric cylinders

Cylinder A is inside cylinder B. L is the length of both cylinders. r_w is the interior cylinder raidus while r_c is the exterior cylinder.

C = (2 \pi \epsilon_r \epsilon_0 L) / ( \ln (\frac{r_c}{r_w}) )