Chapter 16:Electricity

Section 3 – Circuits

–Definition: circuit – a set of components that allow one or more complete paths for electric current to flow.–Any time electricity is flowing, a circuit is present.

Circuits

• When electricity is able to flow freely through a circuit, that circuit “closed”.

• Incomplete circuits will not allow electricity to flow freely. – They are called “open” circuits.

Circuits

• Circuits consist of many different things. • The most common components of a circuit are:– Power Supplies– Wires– Resistors– Bulbs– Switches

• Definition: resistor – a device that blocks SOME (not all) electric current in a circuit.

• Appliances like TV’s, lights, computers…these are all resistors.

Circuit Components

Basic Circuit Symbols (copy these to notes!)

Resistor Wire

Battery or Power Source

BulbOpen Switch

Closed Switch

–Definition: series circuit – a circuit that forms a single pathway.– Electricity can only flow one way in a series

circuit.

Types of Circuits

• Definition: parallel circuit – a circuit that forms multiple pathways for electricity.

–Parallel circuits can have a piece removed from them and still allow electricity to flow in another part of the circuit.

Types of Circuits

• Electric resistance explains why electronics get hot as they run.

• Even conductors cause some resistance.

• As a wire gets thicker, there is less resistance.

Electric Current in wires….

Lots of Resistance Some Resistance Little resistance

• As a wire gets shorter, there is less resistance.

Electric Current in wires….

Lots of Resistance Some Resistance Little resistance

• As a wire gets thicker it can carry more electric current.

Electric Current in wires….