Capacitance

that causes energy to be stored in a magnetic field about the

coil. The energy is stored in such a way as to oppose any

change in current. CAPACITANCE is similar to inductance because

it also causes a storage of energy. A CAPACITOR is a device

that stores energy in an ELECTROSTATIC FIELD. The energy is

stored in such a way as to oppose any change in voltage. Just

how capacitance opposes a change in voltage will be explained

later. However, it is first necessary to explain the principles

of an electrostatic field as it is applied to capacitance.

a. The Electrostatic Field. It was previously learned that.

opposite electrical charges attract each other while like

electrical charges repel each other. The reason for this is the

existence of an electrostatic field. Any charged particle is

surrounded by invisible lines of force, called electrostatic

lines of force. These lines of force have some interesting

characteristics:

(1) They are polarized from positive to negative.

(2) They radiate from a charged particle in straight lines and

do not form closed loops.

(3) They have the ability to pass through any known material.

(4) They have the ability to distort the orbits of tightly

bound electrons.

Figure 26 on the following page represents two unlike charges

surrounded by their electrostatic field. Because an

electrostatic field is polarized from positive to negative,

arrows are shown radiating away from the positive charge and

toward the negative charge. Stated another way, the field from

the positive charge is pushing, while the field from the

negative charge is pulling. The effect of the field is to push

and pull the unlike charges together.

In figure 27 on the following page, two like charges are shown

with their surrounding electrostatic field. The effect of the

electrostatic field is to push the charges apart.

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