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Current, Voltage & ResistanceConductors & Insulators

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Energy in a Circuit...Energy in a Circuit...

is similar to water through pipes

We will learn how to measure the energy in a We will learn how to measure the energy in a circuit and how... circuit and how...

are related.are related.andand

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1.5 V

0.0 V

The potential difference (voltage) is 1.5 V.

Potential Energy (height)

To Lower Energy

Potential DifferencePotential Difference

is a measure of “potential difference.”

1.5 Meters

The unit for voltage is volts (V)

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Higher Potential energy (height)

To Lower Energy

GreaterPotential DifferencePotential Difference

3.0 V

0.0 VThe potential difference (voltage) is 3.0 V.

The higher the energy, the greater the voltage (potential difference).

3.0 Meters

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= 1.5 volts

3.0V ?V

Is the voltage the same in A, C and D cell batteries? Let’s look.

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is the raterate that the electricity moves.

++

How

fast is this water com

ing out?

How fast (speed) is the electricity flowing through these wires?

CURRENTCURRENT ( (II) is measured in ) is measured in AmperesAmperes ((AmpsAmps).).

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Flows in 1 direction Flows 2 directionsAlternating Current (AC)Direct Current (DC)

Current goes back and forth about 60 times per second.Example: Wall socket is 120v

Only Batteries – AAA, AA, C, D CellThese are all 1.5V each, but the difference in size means they should last longer period of time.

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The smaller pipe would have greater resistance to the flow because it has a smaller diameter and

not as much water goes through it.

is anything that opposes the flow of electrons or prevents electricity from moving.

Back to the water analogy…Which of the pipes below would prevent water from traveling the fastest?

Pipe 1: Smaller Diameter Pipe

Pipe 2: Larger Diameter Pipe

Measured in units called Ohms ( ).

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Which of the following do you think would be most resistant to electrical current? Why?

Plastic

Rubber

Glass

These materials DON’T allow current to move easily through them.

Therefore they are called

They have a strong resistance to the flow of electrical current.

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These materials allow electrical charge (current) to move easily through them. They have little resistance to the flow of electrical current.

Which of the following do you think would be the least resistant to electrical current? Why?

Plastic

Rubber

Glass

Therefore they are called

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ResistanceResistance

CurrentCurrent

VoltageVoltage

How Fast?How Fast?

How much?How much?

How much is it How much is it slowed down?slowed down?

Match the word on the left to the phrase on the Match the word on the left to the phrase on the right.right.

(R) in Ohms

(I) in Amps

(V) in Volts