Conductors &
Insulators
RADARS INTERMEDIATE LICENSE COURSE
Conductors and Insulators

What is a conductor?

What is an insulator?

How do they work?
The Atom
Electrons
Things around the outside of the atom
Nucleus
Things in the middle of the atom
Bohr’s Atom
Electrons (Negatively Charged)
Arranged in “shells” around the nucleus
2 electrons in first shell, 8 in second, 18 in
third and 32 in the outer shell
Nucleus
Protons (Positively Charged)
Neutrons (Neutral Charge)
Bohr’s Atom
Number of Protons = Number of Electrons
Charge in the nucleus is balanced by the
charge of the electrons in the outer shells
Bohr’s Atom – Opposites Attract
Electrons in the outer shell are further
away from the pulling force of the
nucleus.
It is electrons in the outermost shell that
we can use to cause current to flow.
Bohr’s Atom – Copper
Copper has an atomic number of 29
This means it has 29 electrons and 29
protons
2 in the first shell
29
8 in the second shell
18 in the third shell
1 in the outer shell
Bohr’s Atom – Copper
This single electron in the outer shell is
very weakly bonded to the atom
29
There are lots of spare slots to fill in the
outer shell
This makes it an ideal conductor
Copper as a conductor
+
_
+
_
+
Potential Difference (Making more electrons available)
CURRENT
_
Other conductors
Silver
Gold
Copper
Aluminium
Brass
Steel
Nickel
Expensive
Excellent
conductors
Relatively
cheap
Very good conductors
Salt water
Some gases
Some liquids with
impurities
Poor but conductive
Insulators
An insulator have very few mobile
electrons so current doesn’t flow
when a potential difference is
introduced
Good insulators
Wood
Nylon
Ceramic
Glass
Plastic
Rubber
Polythene
PTFE
Fibreglass
Where are some of these found in
amateur radio and electronic
applications?
Breakdown!
An insulator can become
conductive :Wet
High Potential Difference
What consequences can this have
on antenna systems?
Discuss the dangers of insulation
breaking down.
Safety First
Human body a good conductor
Muscle tissue – good conductor
Fat – not so good
Heart and nervous system are run from
electrical impulses