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# Magnetism

## Generation of an EMF in a Magnetic Field

Induced EMF Definition An EMF can be induced in a conductor if the conductor cuts across or is cut across by a magnetic field. That is to say,  when there is a relative movement between a conductor and a magnetic field, a current will be induced in the conductor if …

## Magnetic Hysteresis Loop including the B-H Curve

Hysteresis Loop Definition A curve, or loop, plotted on B-H coordinates showing how the magnetization of a ferromagnetic material varies when subjected to a periodically reversing magnetic field, is known as Hysteresis Loop or Magnetization Curve. The term ‘hysteresis’ means to lag behind. In electrical terminology it is used to describe the lag …

## Fundamental Laws of Magnetism

Today, a magnet can be defined as a material or substance that has the power to attract iron, steel, and other magnetic materials. Through laboratory experiments, it was discovered that the greatest attractive force appeared at the ends of a magnet. These concentrations of magnetic force are called magnetic poles. …

## Important Magnetic Units, Terms, Symbols, and Formulas

The following table presents important Magnetic Units, Symbols, and Their Formulas as a reference, or source of information. These formulas play a key role while dealing with magnetic circuits such as Transformers, Inductors. Term or quantity Symbol or abbreviation SI Unit and Formula Flux (lines) ϕ \[Weber\text{ }\left( Wb \right)=\frac{number\text{ …

## Properties of Magnetic Materials

Consider the simple model of the atom in Figure 1. Electrons move around the nucleus like the earth around the sun. This electron motion is a small electric current, and anywhere there is a current, there is a magnetic field (moment). Electrons also spin around their axes like the earth. …

## Comparison between Electrical and Magnetic Circuits

The most important differences between Electrical Circuit and Magnetic Circuit are discussed in this article on the basis of Exciting Force, Current & Flux Density, Lines of Force, Series & Parallel Circuit Behavior, Insulation, Energy, Temperature, and Circuits Representation. The following table keys out the main Differences between Electric and Magnetic …

## Hysteresis Loss | Eddy Current and Core Losses

The area within the hysteresis loop is a product of B and H and this area represents the energy per unit volume that must be used per magnetization cycle to move the domains.  Hysteresis Loss With appropriate constants, the hysteresis loss can be given in watts per unit volume. An …

## Hysteresis Loop | Magnetization Curve

Hysteresis Loop Definition A curve, or loop, plotted on B-H coordinates showing how the magnetization of a ferromagnetic material varies when subjected to a periodically reversing magnetic field, is known as Hysteresis Loop. Hysteresis Definition Hysteresis is the lagging of the magnetization of a ferromagnetic material behind the magnetizing force …

## Absolute and Relative Magnetic Permeability

Permeability is the measure of the ease, with which magnetic lines of force pass through a given material. The ability of a material to concentrate magnetic flux is called permeability and its symbol is the Greek lower case letter μ. Any material that is easily magnetized tends to concentrate magnetic …

## Magnetic Field Intensity | Definition Formula

Magnetomotive force, ℑ , per unit length, is called the magnetic field intensity H. Magnetic Field Intensity Unit Magnetic field intensity is also known as the magnetizing force which is measured is ampere-turns per meter (A-t/m). Of primary concern, however, is the magnetomotive force needed to establish a certain flux density, …

## Magnetic Flux Density | Definition and Formula

Magnetic Flux Density Flux density is the measure of the number of magnetic lines of force per unit of cross-sectional area. While the total amount of the flux produced by a magnet is important, we are more interested in how dense or concentrated, the flux is per unit of cross-sectional …

## Magnetic Flux Definition and Unit

Magnetic Flux is defined as; “a total number of lines of magnetic force passing through any surface placed perpendicular to the magnetic field. It is denoted by φ (Greek Letters Phi). Magnetic Flux Formula The magnetic flux is also defined as the dot product of magnetic field B and vector Area …

## Magnetomotive Force (MMF) Definition

Magnetomotive force is defined as, “The force produced by current through a coil of wire is called magnetomotive force (mmf), as shown in the following figure. It is the force by which a magnetic field is produced. Just as an increase in electromotive force produces more current in a circuit, …