electrical engineering

1. Ch. 24: Electric Current and
Circuits
Vocabulary:
electrical energy, electric current, circuit,
closed circuit, conductor, closed circuit

2. Electric Circuits
• All electric circuits come in
two basic flavors.
• They are either open or
closed.
• Closed circuits are
completely connected, and
the electricity can flow.
• Open circuits have a spot or
spots where they are not
connected and will not
allow electricity to flow.

3. Closed Circuits
• In a circuit we talk about the flow of electricity, it is called
electric current.
• In the simple closed circuit from before the electricity flows
out of the top section of the battery (positive end), through the
wire, into the light bulb (making it light up), then into the next
wire, and back into the bottom of the battery (negative end).
• If everything stay connected (closed) then the electricity will
continue to flow.
• We use wires to carry electric current because they are good
conductors.
• Conductors are materials that allow electricity to flow through
them.
• Wires are usually made out of copper, because copper is an
excellent conductor.

4. Open Circuits
• Open circuits do not allow electricity to flow.
• When a hole happens in the circuit, then the circuit
opens and the electricity cannot flow back into the
battery and the whole operation shuts down.
• This is not always a bad thing.
• Sometimes you don’t want a circuit to be closed all
the time, like on a lamp, you want to be able to sleep
sometime.
• A device called a switch can be placed inside the
circuit that will open or close the circuit whenever
you want.

5. Open Switch vs. Closed Switch

6. Electricity?
• The appliances in your
house are too large to run on
batteries.
• Instead the electricity is
produced in a power plant
and sent through wires into
your house, powering
everything that needs
electricity where you live.
• REMEMBER! Electricity
does not come from wires, it
only travels through them.

7. Questions About Chapter 24
1. Why are switches installed into electric
circuits?
2. Name two places that electricity comes from.
3. What are the two basic types of electric
circuits?
4. What is electric current?
5. Draw a picture of a simple closed circuit.
Include wire, a battery, and a light bulb.