Fundamentals of Capacitors and Electromagnetism

Capacitor Fundamentals and Functions

A capacitor (also known as a condenser) is a composite element consisting of two metal plates separated by an insulating material called a dielectric. When connected to a battery, it acquires tension between its plates and becomes electrically charged. In conclusion, it acts as a DC open circuit but allows AC to drive through. Capacity refers to the property of a condenser to store more or less electricity.

Magnetism and Electromagnetism

Ferromagnetic materials are substances attracted to a magnet. The poles of a magnet are the end points where magnetism is most powerful. Electromagnetism dictates that any electric current is associated with a magnetic field.

Magnetic Fields in Conductors

In a straight conductor, the magnetic field produced is very sparse and weak. However, a conductor in the form of a loop (ring) will form a stronger magnetic field. In a coil, the magnetic field of each loop is added to the next; the resulting field is uniform and very intense in the center of the loop, while magnetic poles are formed at the ends of the coil.

Magnetic Quantities and Units

• Magnetic Flux: Represented by the amount of field force; its unit is the Weber.
• Magnetic Induction (B): The magnetic flux per unit of surface area; its unit is the Tesla.
• Magnetomotive Force (MMF/F): The capacity of a spool as a field generator, which depends on strength and intensity.
• Magnetic Field Intensity (H): Indicates how intense the magnetic field is.
• Reluctance: A symbol indicating the ease or difficulty a material presents to the setting of magnetic field force.

Magnetization and Material Properties

The magnetization curve shows how magnetic induction grows according to the magnetic field. Magnetic saturation is the point where changes in the magnetic field produce only small changes in induction. Magnetic permeability is the power of some ferromagnetic materials to multiply the field; it can be expressed as absolute (the property of the material) or relative (compared to air).

Magnetic Hysteresis and Remanence: Some substances maintain a certain level of magnetic induction even after they are no longer subject to a magnetic field. The coercive field is the opposite field necessary to override this remaining magnetic induction.