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CONDUCTION,
INSULATION AND
PROTECTION
CONDUCTION

Energy (eg. Electrical) transfer from one
material to another by direct contact.

Conductors are materials that allow transfer
to happen. Examples of good conductors are
copper, aluminum, silver and optical fibres.
Transition metals are good
conductors of electricity and
heat.
PRINTED CIRCUITS
 ELECTRICAL
CIRCUIT PRINTED
ON A THIN RIGID BOARD
ONE METHOD HAS BOARDS
COVERED WITH COPPER, THE
CIRCUIT IS THEN ETCHED INTO
THE COPPER AND THEN THE
REST OF THE COPPER IS
DISSOLVED AWAY LEAVING JUST
THE CIRCUIT;
ELECTRIC AND ELECTRONIC
COMPONENTS ARE THEN
SOLDERED INTO HOLES DRILLED
INTO THE BOARDS
MASS MANUFACTURING OF
CIRCUIT BOARDS VIDEO


Printed Circuit Board Video
There are many devices that use circuit
boards: Cell phones, MP3 Players, DVD
players, TV’s, Computers, and the list can go
on….
INSULATION

THE ELECTRICAL FUNCTION
PERFORMED BY A COMPONENT
TO PREVENT THE FLOW OF AN
ELECTRIC CURRENT

PREVENT INJURY AS WELL AS SHORT CIRCUITS

CERAMIC AND PLASTIC ARE GOOD INSULATORS
THAT CAN BE WRAPPED AROUND A WIRE, OR
USED TO CONTAIN ELECTRIC FLOW.
PROTECTION

FUSES AND CIRCUIT BREAKERS ARE
EXAMPLES OF PROTECTION

PROTECTION IS A COMPONENT THAT
STOPS THE FLOW OF CURRENT IN THE
EVENT OF A POWER SURGE
FUSES
• Fuses regulate the amount of amps that go through a circuit.
• When a circuit is performing normally, the electrons will flow through the filament
of a fuse.
• Filaments can be found in many different fuses,
light bulbs, diodes and many other electrical elements.
• If the current intensity is to high the filament will either
melt, or break into two pieces.
• At this point the fuse will need to be replaced.
Breaker
• It is a protective device that
can be reset as many times
necessary, thus it is better
than a fuse as a fuse
needs to be replaced every
time the filament breaks.
• Electrons flow through a
bimetallic strip. If the current
intensity gets to high, the strip
heats up and bends.
• The bending of this strip
makes the breaker shut off
and snap over to the off position.
• When this happens you can go to your breaker panel
and reset the breaker switch.
RESISTANCE IS
MEASUREDC IN OHMS
ELECTRICAL RESISTANCE
RESISTORS
LIMIT THE
FLOW OF ELECTRONS
THROUGH AN
ELECTRICAL CIRCUIT
READING A RESISTOR




ON 4 BANDS RESISTORS- THE 1ST TWO BANDS
TELL YOU THE FIRST TWO DIGITS OF
RESISTANCE (ex. RED=2; BLUE=6)
THE NEXT BAND TELLS YOU WHAT TO
MULTIPLY THOSE NUMBERS BY (ex. RED=100)
LAST BAND IS TOLERANCE FACTOR (EX.
GOLD= ±5%)
THEREFORE A RESISTOR WITH RED, BLUE,
RED, GOLD WOULD HAVE RESISTANCE OF
2600 ohms ±5%
Colour coding on resistors


Resistors are coated with ceramic.
They have color coded bands to
indicate resistance
1st & 2nd band
first two digits of
resistance
3rd band
Number of zeros to add
after the first two
numbers.
2nd
Resistor
3rd
1st
Example:
The resistor on the right
has the following value.
First colour is red, thus
first digit is 2 and the
second colour is orange,
thus the second digit is 3
= 23
The third colour is yellow,
and this digit is 4 we
therefore find 104 =
10000
This resistance would be 10000 X 23
= 230 000 W
Black
0
Brown
1
Red
2
Orange
3
Yellow
4
Green
5
Blue
6
Violet
7
Gray
8
White
9