Download Electrical Fundamentals

ELECTRICAL FUNDAMENTALS
MATTER
Everything in the world is made of matter. Matter is anything that
has mass (weight) and occupies space.
Matter can be made up of a group or series of different atoms to
form a molecule. These groups of atoms (molecules) are
sometimes called compounds. Some types of matter can be
broken down to a single atom while still maintaining the
properties of the original material. These types of material are
called elements.
Matter has three states: Solid, Liquid, and Vapor.
MOLECULE EXAMPLE
Imagine a lake. Now imagine taking the smallest
particle or piece of water from the lake. You
would have a single molecule of water, H2O,
which is made up of two hydrogen atoms and one
oxygen atom.
Not all materials are made up of molecules.
Copper, for example, is made up of a single copper
atom. These are called elements. Each element is
a type of matter that has certain individual
characteristics.
THE ATOM
One of the basic building blocks in the universe for
matter is the atom. All matter - gas, liquid, or solid - is
made up of molecules or atoms joined together. These
atoms are the smallest particle into which an element or
substance can be divided without losing its property.
A single atom consists of three basic components: a
proton, a neutron, and an electron.
Within the atom there is a Nucleus. The Nucleus contains
the protons and neutrons. Orbiting around the nucleus
are the electrons.
An atom is similar to a miniature solar system. As with
the sun in the center of the universe, the nucleus is in
the center of the atom. Protons and Neutrons are
contained inside the nucleus. Orbiting around the
nucleus are the electrons.
ATOM CONSTRUCTION
An atom is similar to a miniature
solar system. As the sun is in the
center of the solar system, so is the
nucleus is in the center of the atom.
Protons and neutrons are contained
within the nucleus. Electrons orbit
around the nucleus, which would be
similar to planets orbiting around
the sun.
NUCLEUS
The Nucleus is located in the center
of the atom (shown in red).
The Nucleus contains the protons and
neutrons.
Orbiting around the nucleus are the
electrons.
PROTONS
Protons are located within the nucleus of
the atom (shown in blue).
Protons are positively (+) charged.
NEUTRONS
Neutrons add atomic weight to an atom
(shown in green).
Neutrons have no electrical charge.
ELECTRONS
Electrons orbit around the nucleus of the atom
(shown in yellow).
Electrons are negatively (-) charged.
Since electrons are lighter than protons and are
outside the nucleus, they can be easily moved
from atom to atom to form a flow of electrons.
Normally electrons are prevented from being
pulled into the atom by the forward momentum
of their rotation. Electrons are also prevented
from flying away because of the magnetic
attraction of the protons inside the nucleus, the
same type of force that keeps the planets
orbiting around the sun.
ELECTRICAL CHARGES
Opposite electrical charges
always attract each other. So
these particles with opposite
charges will tend to move
toward each other. Like
electrical charges always repel.
So particles with like charges
will move away from each other.
Remember: Opposites charges
BALANCED ATOMS
Atoms normally have an equal number of
electrons and protons.
Atoms have no electrical charge. They
are neither positive nor negative. They
are electrically neutral or BALANCED. The
negative charge of the electrons will
cancel the positive charge of the protons,
thus balancing the charge of the atom.
This cancellation of charges creates a
natural attraction or bonding between
the positive proton and the negative
electron.
ION PARTICLES
When an atom loses or gains an electron,
an imbalance occurs.
The atom becomes either a positively or
negatively charged particle called an
ION. These unbalanced charged ION
particles are responsible for electron flow
(electricity).
IONs will take or release an electron to
become balanced again.
ION CHARGE
A positive (+) ION has one less
electron than it has protons.
A negative (-) ION has one more
electron than it has protons.
The positive ION attracts a negative
ION to become balanced. This
attraction or difference in electrical
potential causes electron flow.
ELECTRON ORBITS
Electrons rotate around the atom at
different orbits called Rings, Orbits, or
Shells.
BOUND ELECTRONS orbit the nucleus on
the inner rings. Bound electrons have a
strong magnetic attraction to the nucleus.
FREE ELECTRONS orbit on the outermost
ring which is known as the VALANCE
RING.
FREE ELECTRONS
Only the FREE ELECTRONS in the outermost shell
(Valance Ring) are free to move from atom to
atom. This movement is called ELECTRON FLOW.
These FREE ELECTRONS are loosely held and
can easily be moved to another atom or ion.
Because of their distance from the nucleus, free
electrons have a weak magnetic attraction. Since
this attraction is not as strong to the nucleus as
the bound electrons on the inner orbits, the
electrons move easily from atom to atom.
INSULATORS
An INSULATOR is any material that inhibits
(stops) the flow of electrons (electricity).
An insulator is any material with 5 to 8 free
electrons in the outer ring. Because, atoms with 5
to 8 electrons in the outer ring are held (bound)
tightly to the atom, they CANNOT be easily
moved to another atom nor make room for more
electrons.
Insulator material includes glass, rubber, and
plastic.
CONDUCTORS
A CONDUCTOR is any material that
easily allows electrons (electricity) to flow.
A CONDUCTOR has 1 to 3 free electrons
in the outer ring.Because atoms with 1 to
3 electrons in the outer ring are held
(bound) loosely to the atom, they can
easily move to another atom or make
room for more electrons.
Conductor material includes copper and
gold.
SEMICONDUCTORS
Any material with exactly 4 free flectrons
in the outer orbit are called
SEMICONDUCTORS.
A semiconductor is neither a conductor or
insulator.
semiconductor material includes carbon,
silicon, and germanium.
These materials are be used in the
manufacturer of diodes, transistors, and
integrated circuit chips.
Two Current Flow theories exist. The first is:
ELECTRON THEORY
The Electron Theory states that current flows from NEGATIVE to POSITIVE. Electrons move
from atom to atom as they move through the conductor towards positive.
The second Current Flow theory is:
CONVENTIONAL THEORY
Conventional theory, also known as HOLE THEORY, states that current flows from
POSITIVE to NEGATIVE. Protons or the lack of electrons (the holes) move towards the
negative. (Current flow direction in Hole Theory is the opposite of that in Electron
Theory.)
VOLTAGE
Voltage is the electrical force that moves electrons through a
conductor. Voltage is electrical pressure also known as EMF (Electro
Motive Force) that pushes electrons.
The greater the difference in electrical potential push (difference
between positive and negative), the greater the voltage force
potential.
MEASUREMENT
A VOLTMETER measures the voltage
potential across or parallel to the
circuit.
The Voltmeter measures the amount
of electrical pressure difference
between two points being
measured.
Voltage can exist between two
points without electron flow.
VOLTAGE UNITS
Voltage is measured in units called
VOLTS.
Voltage measurements can use different
value prefixes such as millivolt, volt,
Kilovolt, and Megavolt.
CURRENT (AMPERES)
CURRENT is the quantity or flow rate of electrons moving past a point within one
second. Current flow is also known as amperage, or amps for short.
Higher voltage will produce higher current flow, and lower voltage will produce
lower current flow.
MEASUREMENT
An AMMETER measures the quantity of current flow. Ammeters are
placed in series (inline) to count the electrons passing through it.
Example: A water meter counts the gallons of water flowing through it.
AFFECTS OF CURRENT FLOW
Two common effects of current flow are Heat Generation and
Electromagnetism.
HEAT: When current flows, heat will be generated. The higher the current
flow the greater the heat generated. An example would be a light bulb. If
enough current flows across the filament, it will glow white hot and
illuminate to produce light.
ELECTROMAGNETISM: When current flows, a small magnetic field is
created. The higher the current flow, the stronger the magnetic field. An
example: Electromagnetism principles are used in alternators, ignition
systems, and other electronic devices.
RESISTANCE
Resistance is the force that reduces or stops the flow of electrons.
It opposes voltage.
Higher resistance will decrease the flow of electrons and lower
resistance will allow more electrons to flow.
MEASUREMENT
An OHMMETER measures the resistance
of an electrical circuit or component. No
voltage can be applied while the
ohmmeter is connected, or damage to the
meter will occur.
Example: Water flows through a garden
hose, and someone steps on the hose. The
greater the pressure placed on the hose,
the greater the hose restriction and the
less water flows.
RESISTANCE FACTORS
Various factors can affect the resistance. These include:
LENGTH of the conductor. The longer the conductor, the higher the resistance.
DIAMETER of the conductor. The narrower the conductor, the higher the resistance.
TEMPERATURE of the material. Depending on the material, most will increase resistance
as temperature increases.
PHYSICAL CONDITION (DAMAGE) to the material. Any damage will increase
resistance.
TYPE of MATERIAL used. Various materials have a wide range of resistances.
TYPES OF ELECTRICITY
Two basic types of Electricity classifications:
STATIC ELECTRICITY is electricity that is
standing still. Voltage potential with NO
electron flow.
DYNAMIC ELECTRICITY is electricity that is in
motion. Voltage potential WITH electron
flow. Two types of Dynamic electricity exist:
Direct Current (DC) Electron Flow is in only
one direction.
Alternating Current (AC) Electron flow
alternates and flows in both directions (back
and forth).
DIRECT CURRENT (DC)
Electricity with electrons flowing in only one direction is called Direct Current or DC.
DC electrical systems are used in cars and trucks.
ALTERNATING CURRENT (AC)
Electricity with electrons flowing back and forth, negative - positive- negative, is called
Alternating Current, or AC.
The electrical appliances in your home use AC power.
SOURCES OF ELECTRICITY
Electricity can be created by several means: Friction, Heat, Light,
Pressure, Chemical Action, or Magnetic Action.
*The battery produces electricity through chemical action
*The alternator produces electricity through magnetic action.
* Friction creates static electricity.
* Heat can act upon a device called a thermo couple to create DC.
* Light applied to photoelectric materials will produce DC electricity.
* Pressure applied to a piezoelectric material will produce DC
electricity.
* Chemical Action of certain chemicals will create electricity.