~~NOCACHE~~

====== General Equations ======

See also: [[resource:constants|General constants]]

===== Capacitance =====

General note: <jsm>\epsilon_r</jsm> is the dielectric constant of water, where <jsm>\epsilon_0</jsm> is the dielectric constant of free space. See the [[resource: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

<jsm>C = \frac{\epsilon_0  \epsilon_r  A}{d}</jsm>

==== Concentric cylinders ====

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

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