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.
• 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.
• 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
• 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 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
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 attract,
and like charges repel.
• Atoms always try to remain electrically
balanced.
Atom
• 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.
• 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.
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
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.
LESS THAN
VOLTAGE
BASE UNIT
LARGER THAN
BASIC UNIT
BASE UNIT
Symbol
mV
V
kV
Pronounced
millivolt
Volt
Kilovolt
Multiplier
0.001
1
1,000
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.
Ohms
• 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.
STATIC ELECTRICITY
• Voltage potential with NO
electron flow.
• Example: By rubbing a
silk cloth on a glass rod,
you physically remove
electrons from the glass
rod and place them on the
cloth. The cloth now has a
surplus of electrons
(negatively charged), and
the rod now has a
deficiency of electrons
(positively charged).
DIRECT CURRENT (DC)
• Electricity with
electrons flowing in
only one direction is
called Direct Current
or DC.
• DC electrical
systems are used in
cars.
ALTERNATING
CURRENT (AC)
• Electricity with
electrons flowing
back and forth,
negative - positivenegative, 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.
Only a few of these sources of energy are used in the automobile. The
battery produces electricity through chemical action, and 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.