Automotive Electrical Systems

Camille Joyce O. LumbaBSEd 3F TLE

Fundamentals of Electricity

Introduction

Electricity The word electricity came from a new Latin word “electricus”means AMBER –LIKE.And from the Greek word “electron” meaning AMBER.

Electricity Is a vital commodity on earth.Its usedfulness Transcends human understanding that up to this so called Nuclear age,the usefulness of electricity has not been maximized.

Electricity propels the economic growth and development of any nation.The construction and operation of many industrial and business establishments, factories , plants etc. which has led to massive employment of people is mainly due to electricity.

Nature and Definition of Electricity

Electricity however , has not been accurately defined and recognized by its

effect. Electricity is produced when electrons move through a conductor. This

flow of electrons in the same direction as in a wire is called ELECTRIC CURRENT.

It has been discovered that the speed of electron flow in a wire is 86,000 miles per seconds(mps).

SOURCES OF ELECTRICITY

Natural SourcesArtificial Sources

In the case automotive electricity , we have the storage battery as the main source of electricity. A charging system making use of alternator is also

used to ensure that the battery always operate in full charged condition and to supply the other electrical requirements of the automobile during operation.

Electron: The basic unit of electricity. Voltage: This is the force (or pressure, if you like) of

electricity in the wire. Current: This is the movement of electrons in the wire,

expressed in a unit called the Amp. The greater the rate of movement through the wire, the greater the number of amps.

Resistance: This is a restriction to the movement of electrons through the wire or circuit. The unit of

resistance is called the OHM.The higher the resistance, the more current must flow to overcome it. The more

current which flows through an area of high resistance, the hotter the wire will become, ultimately failing.

IMPORTANT FACT! High resistance is the cause of ALL

electrical failures - with the exception of broken wires and lack

of grounding

Watts: The unit of power in electricity and the product

of Amps x Volts. 

WHY IS THIS IMPORTANT?

Because designers of circuits need to know the amount of current required for a given device (such as a fan, horn, light, etc.) in order to figure out which diameter wire to

use.

EXAMPLE: A 50-watt brake light, operating on 12 volts, will draw 4.1 amps.

(4.1 amps x 12 volts = 50 watts).

IMPORTANT FACT!  This is the only formula you will ever really need to understand

basic electricity, be it in your car or in your house.