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Permanent Magnet & Electromagnet Principles. Electricity/Electronics Technology Department Rondout Valley High School. Outline. Permanent Magnets Poles Magnetic Fields Characteristics of Fields Uses Electromagnets How they are created Magnetic fields Uses. Permanent Magnets.
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Permanent Magnet &Electromagnet Principles Electricity/Electronics Technology Department Rondout Valley High School
Outline • Permanent Magnets • Poles • Magnetic Fields • Characteristics of Fields • Uses • Electromagnets • How they are created • Magnetic fields • Uses
Permanent Magnets • Holds a magnetic force • Can not be turned on and off • Uses • Frig Magnet • Speakers • Electric Motors • Many more….
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
Magnetic field: • The region around a magnet or current-carrying body in which magnetic forces are observable Permanent Magnet S N
Repelling Forces • Like Poles want to repel each other S N N S Magnetic fields collide and push against each other
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
Electromagnet Basics • Current-Carrying Wire • Needs to have electron flow Electromagnetic Field around a wire
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
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
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
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
Putting Electromagnets to Use • Solenoid: • Is an electromagnet with a moveable core called a plunger
Uses for a Solenoid • Electrical Relays • Buzzers • Switches • Locks • Bells
Other uses for Electromagnets • Transformers • Industry • Sensors • Motors
Summary • 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
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