1. Permanent Magnet & Electromagnet Principles
Electricity/Electronics
Yvonne Brannum

2. Outline Permanent Magnets Poles Magnetic Fields
Characteristics of Fields
Uses
Electromagnets
How they are created
Magnetic fields

3. Permanent Magnets Holds a magnetic force Can not be turned on and off
Uses
Frig Magnet
Speakers
Electric Motors
Many more….

4. Magnetic Poles
Refers to the ends of a permanent magnet, either North or South
Determined by its charge (placement of electrons)
Permanent Magnet S N

5. Magnetic field:
The region around a magnet or current-carrying body in which magnetic forces are observable
Permanent Magnet S N

6. Repelling Forces S N N S Like Poles want to repel each other
Magnetic fields collide and push against each other

7. Electromagnets Use electricity to create a magnetic field
They can be controlled (turned on and off)
Their force or strength of field can be controlled

8. Electromagnet Basics Current-Carrying Wire Needs to have electron flow
Electromagnetic Field around a wire

9. Determining the Direction of the Magnetic field
Left-Hand Rule:
Grasp a wire with your left hand with your thumb pointing in the direction of current flow
Your fingers around the wire point in the direction of the field

10. Creating a Larger Magnet
Coils
Each loop of coil has a small amount of magnetic pull
When the loops are added together the coil begins to act as a magnet with poles

11. Electromagnetic Field

12. Strength of Electromagnets
Depends on three main things:
Number of turns in the coil
The more turns in a coil, the stronger the magnet
Amount of current in the coil
If the voltage is increased, so will the current,which will increase the strength of the magnetic field

13. Strength of Electromagnets(cont.)
Permeability of the core material
Permeability: The ability of a material to be magnetized, even temporarily, and to transmit magnetic force
Air would make a weak magnet
Iron would make a strong magnet

14. Putting Electromagnets to Use
Solenoid:
Is an electromagnet with a moveable core called a plunger

15. Uses for a Solenoid
Electrical Relays
Buzzers
Switches
Locks
Bells

16. Solenoid Uses

17. Other uses for Electromagnets
Transformers
Industry
Sensors
Motors

18. Summary
1. Magnets that hold their magnetic forces and can not be controlled are called__________.
Permanent Magnets
2. Refers to the region around a magnet or current carrying device where magnet forces are observed.
Magnetic Field

19. Summary (cont.)
3. How is the direction of a magnetic field determine around a current carrying wire?
Left-Hand Rule
4. What three things determine an electromagnet’s strength?
Number of turns
Current through the coil
Permeability of core material