What is an electromagnet?

What is an electromagnet?

• The basic idea behind an electromagnet is extremely simple: By running electric current through a wire, you can create a magnetic field.

• By using this simple principle, you can create all sorts of things, including motors, solenoids, read/write heads for hard disks and tape drives, and speakers.

Something to think about..

• What is the difference between a permanent magnet and an electromagnet?– Permanent magnets come from nature and are

attracted to any metal which contains iron.– Electromagnets are temporary, their magnetism

is only present when electricity is applied to them.

• This makes electromagnets very useful for different applications.

Anatomy of an Electromagnet• An electromagnet starts with a battery (or some other

source of power) and a wire. What a battery produces is electrons.

• Electrons collect at the negative end of the battery, and, if you let them, they will gladly flow to the positive end. Electrons will flow from the negative side of the battery to the positive side as fast as they can.

• A small magnetic field is generated in the wire. It is this small magnetic field that is the basis of an electromagnet.

Types of Electromagnets

What is a solenoid?

When copper wire is coiled, the coil of wire is

called a solenoid. When electricity passes through the coil, a magnetic field is produced.

(SEE THE PICTURE) The magnetic field set up a by a solenoid (coil of wire) carrying a current is

very similar to the magnetic field of a bar magnet.

A quick review...

• Permanent magnets never loose their magnetism unless destroyed.

• Electromagnetism is created when electrons flow within an electrical circuit.

• Electromagnets can be used for a number of different applications.

• Solenoids are current carrying coils of wire.

What is a current carrying coil of wires called?

A. ElectromagnetB. SolenoidC.Voltaic PileD.Ferromagnetic

How are electricity and magnetism related?

A. They were discovered at the same time.

B. Electric current produces a magnetic field.

C. They both have fields, poles, and domains.

D. They are not related.