Electromagnetic Induction

1. If a magnet is moved into a coil of wire a current is induced in the wire.

2. If the magnet is moved out of the coil the direction of the current is reversed

3. A wire, or coil of wire, cutting through a magnetic field will generate a voltage. This induced voltage causes a current to flow through the wire

Electromagnetic InductionElectromagnetic InductionElectromagnetic InductionElectromagnetic Induction

Electromagnetic Induction











The size of the induced voltage can be increased if;

• the wire is moved faster• the magnet is stronger• the number of turns on the coil is

increased• the area of the coil is greater

Increasing the voltageIncreasing the voltageIncreasing the voltageIncreasing the voltage

Increasing the voltage





1. Electricity is generated by rotating a coil of wire in a magnetic field or by rotating a magnet inside a coil of wire. This is how a generator works

Generators and DynamosGenerators and DynamosGenerators and DynamosGenerators and Dynamos

Generators and Dynamos

Generating ElectricityGenerating ElectricityGenerating ElectricityGenerating Electricity

Generating Electricity

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Generator

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Dynamo

1. Transformers can be used to change the voltage of an a.c. supply.

2. A changing magnetic field in the primary coil induces a voltage in the secondary coil

3. Transformers only work with alternating voltage

TransformersTransformersTransformersTransformers

Transformers

TransformersTransformersTransformersTransformers

Transformers

1. Step-up transformers produce high voltages so that little energy is lost in power lines (National Grid)

2. Step-down transformers reduce voltages before the electricity reaches our homes

3. Primary voltage/Secondary voltage = Number of turns on primary/Number of turns on secondary

Step-up & Step-down TransformersStep-up & Step-down TransformersStep-up & Step-down TransformersStep-up & Step-down Transformers

Transformers

Step-up & Step-down TransformersStep-up & Step-down TransformersStep-up & Step-down TransformersStep-up & Step-down Transformers

Transformers

Step up TransformerStep up TransformerStep up TransformerStep up Transformer

Step up transformer

Step down TransformerStep down TransformerStep down TransformerStep down Transformer

Step down transformer

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Electromagnetic Induction

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