Download III. Electrical Circuits

Electrical Circuits
III. Electrical Circuits
Circuit components
 Series circuits
 Parallel circuits
 Household circuits
Circuits
 Electric Circuit – A complete closed path
through which electric charges flow
 Parts of a circuit – all circuits need three
basic parts
 Energy source – battery or electricity
produced by a power plant
 Wires - conductors
 Load – light bulb, radio, tv
Circuit Components
A - battery
B - switch
C - light bulb
D - resistor
Circuits
 Switches – a switch is used to open or
close a circuit.
 In order for electrons to flow, the
switch must be closed or ‘turned on’
 In order for electrons to NOT flow, the
switch must be open or ‘turned off’
Circuits
 One circuit may connect and carry
many ‘loads’
 Think about it…I have 4 computers, 3
lamps, a projector and the ceiling lights
that are used each day
Circuits
 Circuits are often divided into two types:
Parallel Circuits and Series Circuits
 Series Circuits – all components are
connected to a single loop. The
charges only flow through one path
 Parallel Circuits – loads are
connected side by side. Charges
have more than one path to travel
Series Circuits
 Series Circuit
 current travels in a single path
• one break stops the flow of current
 current is the same throughout circuit
• lights are equal brightness
 each device receives a fraction of the
total voltage
• get dimmer as lights are added
Parallel Circuits
 Parallel Circuits
 current travels in multiple paths
• one break doesn’t stop flow
 current varies in different branches
• takes path of least resistance
• “bigger” light would be dimmer
 each device receives the total voltage
• no change when lights are added
Household Circuits
 Combination of parallel circuits
 too many devices can cause wires to
overheat
 Safety Features:
 fuse - metal melts, breaking circuit
 circuit breaker - bimetallic strip bends
when hot, breaking circuit