Download Circuit notes

Which bulb will light?
Explain your choice on your paper.
What is a circuit?
• If you want electricity–you need a circuit.
And, if you want a circuit you ALWAYS
need two things: a power supply and a
conductor.
• Most circuits also have an electrical device
and a switch.
What is a circuit?
• Power Supply: (Battery) “Pump”- adds
energy to electrons in the atoms of the wire
• Conductor: (Wire)- The material where all the
atoms and electrons are located.
• Electrical Device: (Light Bulb)- Uses
electricity to perform a function
Open Circuit (“Off”)
• If the switch is open, there is no force
directing electrons down the path, so they
just keep orbiting the nucleus, or they drift
around randomly. Electricity can't flow at
times like this.
Closed Circuit (“On”)
• If the switch is closed, and all parts of the
circuit are connected, electricity can flow.
• Electrons are "pushed" through the circuit
by the power supply adding energy to the
electrons.
• We call that "push" voltage–that's why
electrical power is measured in volts!
Circuit Diagram
battery
_
+
bulb
In a closed circuit, current
flows around the loop
Closed Circuit (“On”)
Simple Circuits
• Series circuit
–All in a row
–1 path for
electricity
–1 light goes out
and the circuit
is broken
Simple Circuits
• Parallel circuit
–Many paths
for electricity
–1 light goes out
and the others
stay on
Series and Parallel Circuits
• Series Circuits
– only one end of each component is connected
– e.g. Christmas tree lights
• Parallel Circuits
– both ends of a component are connected
– e.g. household lighting