Cylindrical Capacitor

For a cylindrical geometry like a coaxial cable, the capacitance is usually stated as a capacitance per unit length. The charge resides on the outer surface of the inner conductor and the inner wall of the outer conductor. The capacitance expression is

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For and dielectric constant the capacitance per unit length is For a length of L = m the capacitance is 		Index

Capacitor Concepts
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Cylindrical Capacitor

The capacitance for cylindrical or spherical conductors can be obtained by evaluating the voltage difference between the conductors for a given charge on each. By applying Gauss' law to an infinite cylinder, the electric field outside a charged cylinder is found to be

The voltage between the cylinders can be found by integrating the electric field along a radial line:

From the definition of capacitance, the capacitance per unit length is defined as
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