ABC of electricity

About electricity for the "Dummies"

Electrical current is directed motion of negatively charged elementary particles - electrons from one pole of a closed electrical circuit to another. The electrons that can move, exist only in certain substances called conductors. Substances that do not contain free electrons, belong to the category of dielectrics (insulators).

To movement of free electrons in the conductor from one pole to another to be possible, there must exist between the poles of a potential difference or voltage. It can be likened to a certain pressure pushes the electrons. To continuously maintain the flow of current in the closed circuit, the source of the electromotive force, which generates electric power by converting it into other forms of energy.

The number of electrons passing through the cross-section in unit time can be more or less significant. It is the strength - strength of the current.

Depending on the material, size and length of the material passing current conductor has a higher or lower resistance. It appears, in particular, in the heating conductor.

The longer the wire, the greater the resistance. But the larger section of the conductor, the smaller the resistance.

It characterized by power source capacity, i.e. the amount of power that it generates per unit time. Electrical device (device), the consumed electric power, is also characterized by power.

Voltage is measured in volts (V).

The power of (value) of the current is measured in amperes (A).

Resistance is measured in ohms (ohm).

Power is measured in watts (W). 1000-watt is 1 kilowatt (kW).

The development and energy consumption measured in kilowatt hours (kWh). (Do not confuse them with kilowatts).

The following dependencies exist between these quantities:

1.   The current value is equal to the voltage applied to the ends of the conductor divided by the resistance (Ohm's law).

2.   Electrical power is the product of voltage to current.

3. The amount of electricity consumed is equal to the product of the electrical power for the duration of its work.

4. The amount of heat from the transformed electric energy in proportion to a current value in the erected second degree, the resistance of the conductor and time. For example, when the current is increased twice, four times is allocated more heat.

On the nameplate electrical products, as well as instructions for its use must be indicated its nominal data: voltage, power (or current value), and others.

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