Electromagnetic Induction

Electromagnetic Induction Electromagnetic Induction • If a magnet is moved into a coil of wire a current is induced in the wire. • If the magnet is moved out of the coil the direction of the current is reversed • 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 Induction Electromagnetic Induction

Increasing the voltage Increasing the voltage • 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 voltage Increasing the voltage

Generators and Dynamos Generators and Dynamos • 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

Generating Electricity Generating Electricity

Generator Generator

Dynamo Dynamo

Transformers Transformers • Transformers can be used to change the voltage of an a.c. supply. • A changing magnetic field in the primary coil induces a voltage in the secondary coil • Transformers only work with alternating voltage

Transformers Transformers

Step-up & Step-down Transformers Transformers • Step-up transformers produce high voltages so that little energy is lost in power lines (National Grid) • Step-down transformers reduce voltages before the electricity reaches our homes • Primary voltage/Secondary voltage = Number of turns on primary/Number of turns on secondary

Step-up & Step-down Transformers Transformers

Step up Transformer Step up transformer

Step down Transformer Step down transformer

Electromagnetic Induction