Magnetic field linesMagnets
Current in a coil
Permanent Magnet Electromagnet Magnets and Electricity
Electric current makes a magnetic field
Strength of field
depends on current
and number of windings
Iron bar has magnetic domains
that are normally randomly oriented.
They can be oriented by an external
This amplifies the total magnetic strength
of the electromagnet Magnets and Electricity
Changing magnetic field induces an electric field.
magnet in and out
Changing magnetic field inside coil
induces voltage across the coil.
This voltage (and current) can power
an electrical load (light bulb) Lenz’s Law
Lenz’s Law: Current induced by a changing magnetic field
always produces a magnetic field that opposes
If I push the magnet into the coil, the coil will
try to push back.
I need to do work on the magnet, this work
gets transferred into electrical energy.
Use this to make a generator Generator
Lenz’s law: harder to
Coil a large loadere is
coil Transformer core coil
AC voltage in AC voltage out