Make your own free website on Tripod.com

Basic Electricity


By: The Bureau of Naval Personnel, 1970
ISBN: 0-486-20973-3

Atom Ion Conductor
SemiConductors ElectroStatic Voltage
Conductance Inductance Capacitance

p. 12

The Atom is the smallest particle that makes up that type of material called an Element. An element retains its chemical characteristics when subdivided into atoms.

The core of the atom is called the Nucleus and most of the mass of the atom is concentrated within the Nucleus, which consists of Protons and Neutrons.

    Atoms contain:
  1. Protons - are positive
  2. Neutrons - are neutral
  3. Electrons - negative

Normally there is one Proton for each Electron in the Atom. So the net positive charge of the Nucleus is balanced, by the net negative charge of the Electrons whirling around the Nucleus. Thus the Atom is electrically neutral.

p. 13

If the Atom loses an Electron, it becomes positively charged and is referred to as a Positive Ion (Cation). Conversely, if the Atom gains an Electron, it becomes negatively charged and is referred to as a Negative Ion (Anion).

An Ion is a small particle of matter having a positive or negative charge.

Conductors easily permit the free motion of large numbers of their electrons. Electrical energy is transferred through conductors, by means of the movement of free electrons that migrate from atom to atom, inside the conductor.

p. 14

Substances containing few free electons are called Poor Conductors, NonConductors, Di-Electrics, or Insulators. There is no sharp dividing line between insulators and conductors, since varing degrees of electron motion exists in all matter.

p. 15

SemiConductors are neither good conductors, nor good insulators. Their Conductance (ability to conduct) increases, as temperature or pressure rises; because the energy exchange lossens more electrons, which are then available for conduction.


ElectroStatic Force

When two bodies of matter have unequal charges and are near one another, an electric force is exerted between them, because of their unequal charges. However, since they are not in contact, their charges cannot equalize.

The existance of such an electric force, where current cannot flow, is called an ElectroStatic Force, which becomes Static Electricty when the objects make contact.

p. 16

The space between and around charged bodies, in which their influence is felt, is called an Electric Field Of Force (ElectroStatic Force). The field extends between positive and negative charges and always terminates on material objects.

p. 17

Magnetism is the ability of a substance to attract a known magnetic substance such as: Iron, Steel, Nickel, Cobalt, etc.. All magnets have two points of maximum attraction, called Magnetic Poles.

p. 21

Magnetism is also a measure of the net difference in a material's electron spin directions.

If an atom has equal numbers of electrons spinning in opposite directions, the magnetic fields surrounding each electron cancel one another, and the atom is unmagnetized. However, if more electrons spin in one direction than the other, the atom is magnetized.

p. 27
    Forces that cause free electrons to move in a condutor, as an electric current are:
  1. ElectroMotive force (EMF)
  2. Voltage (EMF expressed in Volts)
  3. Difference in Potential

When a difference in potential exists between two charged bodies that are connected by a conductor, electrons will flow along the conductor.

The direction of flow is always from the negatively charged body to the positively charged body and will continue until the two charges are equalized and the potential difference no longer exists.

p. 28

Common methods of producing ElectroMotive Force

  1. Friction - Voltage produced by rubbing two materials together
  2. Pressure (PiezoElectricity) - Voltage produced by squeezing certain Crystals
  3. Heat (ThermoElectricity) - Voltage produced by heating the junction where two unlike metals are joined
  4. Light (PhotoElectricity) - Voltage produced by light striking photosensitive substances
  5. Chemical Action - Voltage produced by chemical reaction in a battery
  6. Magnetism - Voltage produced in a conductor when the conductor moves through a magnetic field, or a magnetic field moves through the conductor in such a manner as to cut the magnetic field's line of force

p. 32

Current (I) is directly porportional to the applied voltage; if voltage doubles, current also doubles.

The drift or flow of electrons through a conductor is called electric current or electron flow.

p. 33

Resistance (R) is opposition to the flow of electric current through the conductor. Generally, an increase in temperature increases resistance.

Conductance (G) is the ability of a material to pass electrons; Conductance is exactly the opposite of Resistance and is mathematically expressed as its reciprocal.

A number's reciprocal is obtained by dividing the number into one: ([G = 1/R] and [R = 1/G]).


p. 58

Ohm's Law
Current is Directly proportional to the applied voltage and Inversely proportional to the circuit's resistance; if resistance doubles, then current is cut in half. Expressed as the equation: I = V/R

p. 171

Inductance is the property of an electrical conductor that opposes any change in current flow. Inductance is similar to the physical property of inertia, which opposes any change in velocity. An Inductor stores energy in an ElectroMagnetic Field.

p. 189

Capacitance is the property of an electrical device or circuit that tends to oppose a change in Voltage.

Capacitance is also a measure of the ability of two conducting surfaces, separated by some form of non-conductor (Di-Electric), to store an electric charge.

A Capacitor (C) stores an electric charge in an ElectroStatic Field.



Medical Texts
Anatomy | Immune System | Lymphocytes | Meds
MHC | Movement | Cranial Nerves | Physiology


MS Glossary ThJuland's MSers' Glen - Our CyberHome Page Top The Glen's Gallery: Come & Share Our Stories MS Files MS Abstracts Site Index


Abstracts
ANS | Bladder | Cognition | Fatigue | Fluid | Genetics
Interferons | IVIG | Nitric Oxide | Optic Neuritis | Pain
Physiology | Prions | Prognosis | ReMyelinate | Steroids
Stress | Treatments | TNF | Uric Acid | Viruses



Copyright 1997 - 2011:
Permission is granted to MS Societies and all MSers to utilize information from these pages provided that no financial reward is gained and attribution is given to the author/s.