ELECTRICITY AND
MAGNETISM
Friday, February 26, 16
ELECTROMAGNETS
•
An electromagnet is a current-carrying wire wrapped around
an iron core.
•
To increase the strength:
•
Increase the current
•
Using a larger core
•
Increasing number of coils
•
The magnetic field of an electromagnetic is turned on or off when
the electric current is turned on or off.
•
Doorbells and high-speed trains use electromagnets to operate
Friday, February 26, 16
MAGNETS PUSH AND PULL
CURRENT
•
Current-carrying wires produce a magnetic field that acts the
same way as a magnet’s magnetic field.
•
Two current-carrying wires can attract or repel each other as if
they were two magnets.
•
The magnetic field around a wire causes it to be pushed or pulled
by a magnet, depending on the direction the current is flowing in
the wire.
•
An electric motor (device that converts electrical energy into
kinetic energy) runs by using the magnetic field formed by a
current-carrying wire formed into a loop.
Friday, February 26, 16
USING MAGNETS TO CREATE
CURRENT
•A
generator uses a magnetic field to turn motion into
electricity.
• An
alternating current (AC) changes from positive to negative
due to a looped wire changing direction of motion.
•A
direct current (DC) electrons flow in one direction
•A
generator can produce both DC and AC current.
• Large
Friday, February 26, 16
power plants produce AC current.