you need

- - knowledge capacity or geometrical and physical parameters of the capacitor;
- - knowledge of energy or charge on the capacitor.

Guide

1

Find the voltage between the plates of the capacitor, if you know the current value of their accumulated energy, as well as its capacity.Energy stored by a capacitor can be calculated by the formula W = (C ∙ U²) / 2, where C - capacity, and U - the voltage between the plates.Thus, the voltage value can be obtained as the square root of twice the value of the energy divided by the capacitance.That is, it is equal to: U = √ (2 ∙ W / C).

2

energy stored capacito
r may also be calculated based on the value of the contained charge (amount of electricity), and a voltage between the electrodes.The formula that defines the relation between these parameters is of the form: W = q ∙ U / 2 (where q - the charge).Therefore, knowing the energy and charge the capacitor, can calculate the voltage between its plates according to the formula: U = 2 ∙ W / q.

3

Since the charge on the capacitor is proportional to both the applied voltage to its plates and capacity (it is defined by the formula q = C ∙ U), then knowing the charge and capacitance, and voltage can be found.Accordingly, for the calculation using the formula: U = q / C.

4

For the voltage on the capacitor with known geometrical and physical parameters, first calculate its capacity.For a simple parallel plate capacitor consisting of two conductive plates separated by a dielectric, the distance between which is negligible compared to their dimensions, the capacitance can be calculated by the formula: C = (ε ∙ ε0 ∙ S) / d.Here, d - the distance between the plates, and S - area thereof.The value ε0 - dielectric constant (a constant equal to 8,8542 • 10 ^ -12 F / m), ε - relative dielectric constant of the space between the plates (you can learn from the physical directories).Calculating the capacity, calculate the voltage of one of the methods described in steps 1-3.

Note

To obtain correct results when calculating the voltage between the capacitor plates, prior to the calculation leads all parameters in SI.