Circuit—A
closed, conducting path that electricity flows through
· 
Series
Circuit—current has only one loop
to flow through; everything is wired one after another
o
ex. holiday
lights: if one goes out, they all go out
· 
Parallel
Circuit—contains two or more branches
for the current to flow through
o
ex. a house: individual things can be turned off without
affecting the entire circuit.
Fuses and Circuit Breakers—Guard against overheating of wires and prevent fires
· Fuse—small piece of metal that melts if it gets too hot
·
Circuit breaker—piece of metal bends when hot and opens the circuit
Electricity is easily changed
to other forms of energy such as mechanical, thermal, and light energy—that’s
why it’s so good!
· Electrical
power—the rate at which electricity is changed into other forms of
energy
o
units=Watts (W)
o
Power = current x
voltage (P = IV)
· Energy is how much
electricity is used
o
Unit =
kilowatt-hours (kWh)
o
Energy = power x
time (E = Pt)
o
Use a 50W fan for
3 hours: Energy = 0.05kW x 3h = 0.15 kWh
