Contact Points and Light
Bulbs
Physics First
Unit 1 Electricity
Contact Points
 All electrical points have contact points
 Contact points- allow electrical current to
flow
 Inside the device there is a pathway
(without breaks) so current can flow
Contact Points
 All devices must have
at least 2 contact
points (some have
more)
 One point allows
current to flow in while
the other allows
current to flow out
 Contact points must
be separated by
some insulator
Anatomy of a Light Bulb
 3. filament wire- current
passes through and
creates heat which turns
to light
 4 and 5- contact wires
that connect to filament
 9 and 11- outside contact
points insulated by 10
 8- wire connected to
inside contacts
Anatomy of a Light Bulb
 1. Glass bulbprotector
 2. Inside gas- does
not allow the filament
to burn out
 6. Support wires- no
electrical purpose
 7. Stem- glass mount
Symbols
 Resistor- (light bulb,
motor, buzzer) device
that a current can
cross
Symbols
 Wire
 Battery
Symbols
 When a switch is
opened or closed we
must show it in our
circuit diagrams