Electricity ISTE

Electricity

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Learning Objectives

• Define Voltage, Current, and Resistance and their relationship using Ohm’s Law.

• Apply Ohm's Law to calculate values in simple circuits.

• Differentiate between series and parallel circuits.

• Distinguish between Alternating Current (AC) and Direct Current (DC).

Key Vocabulary

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Voltage (V)

The energy per unit charge from a power source. Measured in volts (V).

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Current (I)

The flow of electric charge through a conductor. Measured in amperes (A).

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Resistance (R)

The opposition to the flow of electric current. Measured in ohms (Ω).

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Ohm’s Law

Current is proportional to voltage and inversely proportional to resistance.

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Series Circuit

A circuit where components form a single path for current flow.

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Parallel Circuit

A circuit providing multiple paths for current, with components on different branches.

Key Vocabulary

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Direct Current (DC)

Electric charge that flows in a single, constant direction.

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Alternating Current (AC)

Electric charge that periodically reverses direction.

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Electromagnet

A magnet created by running an electric current through a coil of wire.

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Motor

A device that converts electrical energy into mechanical energy.

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Generator

A device that converts mechanical energy into electrical energy.

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Understanding Ohm's Law

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Multiple Choice

According to Ohm's Law, if the voltage in a circuit is increased while the resistance remains constant, what happens to the current?

• It increases

• It decreases

• It stays the same

• It becomes zero

Using the Ohm's Law Formula

Multiple Choice

What is the correct formula to find the resistance in a circuit if you know the voltage and current?

• $$R = V * I$$

• $$R = I / V$$

• $$R = V / I$$

• $$R = V + I$$

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Circuit Diagrams and Symbols

• These diagrams are like blueprints for electrical circuits.

• A battery is a long (+) and a short (-) line.

• A resistor is a zigzag line; a switch is a lever.

• Wires are straight lines connecting all the parts.

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Multiple Choice

In a circuit diagram, what does a zigzag line typically represent?

• A battery

• A switch

• A wire

• A resistor

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What are Series Circuits?

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Multiple Choice

What happens to the other light bulbs in a simple string of Christmas lights if one bulb fails?

• They all go out

• They get brighter

• They stay lit

• They get dimmer

Parallel Circuits

• Current has multiple paths to flow in a parallel circuit.

• The voltage is the same across all branches of the circuit.

• If one part fails, the other branches keep working.

Multiple Choice

Which of the following is a key advantage of parallel circuits, making them suitable for household wiring?

• The total resistance is very high.

• If one appliance fails, the others continue to work.

• They use less wire than series circuits.

• The current is the same through every appliance.

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Comparing Series and Parallel Circuits

Series Circuit

• Current is the same, but voltage divides across components.

• Total resistance is the sum of all resistances.

• A failure in one part stops the entire circuit.

Parallel Circuit

• Voltage is the same, but current divides among branches.

• Total resistance is less than the smallest resistor.

• If one branch fails, the others keep working.

Multiple Choice

In which type of circuit does the total resistance increase when you add more resistors?

• Series Circuit

• Parallel Circuit

• Both types of circuits

• Neither type of circuit

AC vs. DC

• In Direct Current (DC), charge flows in just one direction.

• Alternating Current (AC) periodically reverses its direction.

• DC is from batteries, while AC powers our homes.

Multiple Choice

Which type of current is supplied by a standard battery?

• Alternating Current (AC)

• Direct Current (DC)

• Both AC and DC

• Neither AC nor DC

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Electromagnetism: Motors and Generators

• An electric current in a wire coil creates a controllable magnet.

• Electric motors use this magnet to create motion from electricity.

• Generators do the reverse, using motion to make electricity.

• Motors convert electrical to mechanical energy; generators do the opposite!

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Multiple Choice

What is a device that converts mechanical energy into electrical energy called?

• A motor

• An electromagnet

• A generator

• A resistor

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Common Misconceptions

Misconception

• Voltage and current are the same thing.

• Higher resistance means more power.

• Batteries push out a constant current.

Correction

• Voltage is the pressure that causes current to flow.

• Higher resistance reduces current, which can limit power.

• Batteries provide constant voltage, not constant current.

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Summary

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4