Electrical Fundamentals Module 3: Magnetism

Using magnetic materials to redirect magnetic flux, preventing it from passing through a certain area.

A measure of how difficult it is for magnetic flux to pass through a material.

A material's ability to allow magnetic field lines to pass through it.

A magnet that loses its magnetism when the external magnetic field is removed.

A magnet that retains its magnetism even when the external magnetic field is removed.

When all magnetic domains are aligned, and further magnetization force won't increase magnetic flux (strength).

A loop tracing the relationship between magnetising force and flux density in a material when an alternating magnetic field is applied.

Tiny regions inside a magnetic material where the magnetic fields are aligned.

Materials that exhibit strong magnetic properties, easily becoming magnetized.

The process of becoming magnetized, or the extent to which a material is magnetized.

Halving the length of an electromagnetic coil doubles the force.

The amount of magnetization a material retains when the magnetizing field is removed.

The base unit of magnetic field strength is ampere-turns per meter (At/m).

Same as remanence; amount of magnetic flux density a material retains after removal of magnetising force.

The reverse magnetising field needed to remove all the magnetization in a material.

Field intensity (H) is calculated as magnetizing force (MMF) divided by length.

A measure of the magnetic field passing through a surface.

A material with high remanence and coercivity, that keeps its magnetism.

Materials with low retentivity, magnetization easily lost.

The base unit of magnetic flux is the weber (Wb).

The magnetic flux density remaining in a material after the magnetising force is removed.

Represents the number of magnetic field lines passing through a unit area.

The standard unit for flux density is the tesla (T).

A magnetic field created by a current-carrying wire.

1 Tesla equals 10,000 Gauss. Gauss is an older unit.

A typical speaker magnet has flux density around 1 Tesla.

A material where molecular magnets' forces cancel each other out, resulting in no overall magnetic effect.

A material where most molecular magnets are aligned in the same direction, creating a north and a south pole.

A theory proposing that stroking a material with a magnet aligns molecular magnets, creating a stronger magnetic field.

A modern theory explaining magnetism based on electron spin and the alignment of magnetic domains.

The intrinsic angular momentum of an electron, which creates a magnetic field.

Tiny regions within a material where electron spins are aligned in the same direction.

Magnets made from magnetic materials, often iron or steel alloys, usually magnetized electrically.

Difficult to magnetize but retain their magnetism after the magnetizing force is removed.

Easily magnetized but lose most of their magnetism when the magnetizing force is removed.

The ends of a magnet where the magnetic force is strongest.

The points on Earth where the Earth's magnetic field is strongest.

Earth's magnetic field acts like a giant bar magnet, with its magnetic poles offset slightly from its geographic poles.

The magnetic pole that attracts the north-seeking pole (or north pole) of a compass.

Like magnetic poles repel each other, and unlike magnetic poles attract each other, similar to Coulombs law for charges.

Imaginary lines used to visualize and describe the magnetic field around a magnet.

A device with a freely rotating magnetised needle that points towards the Earth's magnetic North Pole.

The pole of a magnet that aligns with the Earth's North Magnetic Pole. Often called simply the 'North pole'.

Use charged capacitor banks discharged through a coil to create a high-current, short-pulse magnetic field.

The process of removing magnetism from a material, achieved by various methods, including heating above Curie temperature, reversing magnetic field, or mechanical disturbance.

The temperature at which a ferromagnetic material loses its ferromagnetic properties.

Low magnetising force, only practical for Alnico or small sections of Ceramic materials.

Using materials to redirect magnetic fields, protecting sensitive instruments.

The strength of a magnetic field, directly related to the electric current flowing.

The magnetic field is strongest near the wire and weakens as you move away.

A magnetic field exists around a current-carrying conductor only while the current flows.

A rule to determine the direction of the magnetic field around a current-carrying conductor.

Parallel wires with current flowing in the same direction attract each other.

Coiling a wire creates a stronger magnetic field due to the magnetic fields combining.

The process of becoming magnetized, or the extent to which a material is magnetized.

The process of losing magnetism.

Using magnetic materials to redirect magnetic flux, preventing it from passing through a certain area.

Different types of materials with varying magnetic properties.

A temporary magnet created by an electric current.

Consists of a coil of wire wrapped around a ferromagnetic core.

A method for determining the direction of a magnetic field around a current-carrying conductor.

The driving force that creates a magnetic field.

A measure of the magnetic field intensity.

A measure of the number of magnetic field lines passing through a unit area.

A material's ability to allow magnetic field lines to pass through it.

A graph showing the relationship between magnetizing force and flux density in a material.

The ability of a material to retain magnetism when the external field is removed.

The reverse magnetizing field needed to demagnetize a material completely.

A measure of how difficult it is for magnetic flux to pass through a material.

The point where all magnetic domains are aligned, and further magnetization force won't increase magnetism..

Electric currents induced in a conductor by a changing magnetic field.

Precautions for handling and storing magnets safely.