Download Chapter 6 Electricity: Electrical Circuit

Chapter 6 Electricity
Lesson 2 – Electric Circuits
Main Idea
Electric current is a flow of electrical charges. Electric current will only flow
through a complete circuit.
Vocabulary
o Electric current (298) – a flow of electrical charge
o Circuit (299) – path along which electric current flows
o Series circuit (300) – electrical charges flow in the same direction
along a single path
o Parallel circuit (302) – a circuit in which the electrical current flows
through more than one path
o Voltage (304) – the strength if a power source
o Resistance (304) – ability of a substance to oppose or slow down
electric current
What is electric current?
Main Idea
A flow of electrical charges is known as electric current. Current only flows
through closed circuits.
Supporting Details
1. A flow of electrical charges is known as an electric current.
2. Electric currents keep charges moving like water flowing in a river or a
stream.
3. Circuit
a. The path along which electric current flows is a circuit.
b. A simple circuit has three basic parts
i.
Power source such as the battery
ii.
Connectors, such as wires
iii.
Switch turns electric currents on an off
4. Open and Closed Circuit
a. A complete, unbroken circuit is called a closed circuit
b. A circuit with a break is an open circuit. Electric charges cannot flow
in an open circuit.
What is a serial circuit?
Main Idea
Serial circuits have one path for electric current.
Supporting Details
1. A series circuit is when all electric charges flow in the same direction
along a single path.
2. The parts of a series circuit are connected in one loop.
3. The electric current moves from the power source, through the wires, to
one load. It then moves to another load. It returns through a wire to the
power source.
4. A circuit is a series circuit as long as all of the parts are connects one
after another.
5. If any part of a series circuit is removed or broken, the circuit is open and
no current can flow through it.
What is a parallel circuit?
Main Idea
Parallel circuits have many paths.
Supporting Details
1. A parallel circuit is a circuit in which the electric current flows though
more than one path.
2. The different paths are often called branches.
3. Some of the electric current flows through one branch while some flows
through the other branches.
4. If any branch of a parallel circuit is removed or breaks, electric current
still flows through the other branches.
5. Many circuits in electrical devices are a combination of series and parallel
circuits.
What affects electric current?
Main Idea
The amount of current that flows through a circuit depends on voltage and
resistance.
Supporting Details
1. The amount of electric current that can flow through a circuit depends on
voltage and resistance.
2. Voltage
a. Voltage is the strength of a power source.
b. A power source with more voltage can produce more electric current.
c. Voltage is measured in volts.
i.
A D cell battery has 1.5 volts.
ii.
Most wall outlets which gets power from a power plant have 120
volts.
3. Resistance
a. Resistance is the ability of a substance to oppose or slow down electric
currents.
b. Increasing the resistance of a circuit decreases the flow of electrical
charges through it.
c. Resistance allows electrical energy to be changed into other forms of
energy such as light and heat.
d. Copper wires are good conductors. They have little resistance so they
can carry a great deal of electric current.
e. Rubber is an insulator that has a large amount of resistance.
4. Short Circuit
a. A path with no resistance is sometimes called a short circuit.
b. A short circuit can stop the rest of the circuit from operating properly.
c. The wires may heat up and may cause a fire.