ELECTRICAL TERMINOLOGY

Basic Electrical Theory ELECTRICAL TERMINOLOGY ELECTRICAL TERMINOLOGY Knowledge of key electrical terminology is necessary to fully understand principles in electrical science. EO 1.2 DEFINE the following terms: a. Conductor b. Insulator c. Resistor d. Electron current flow e. Conventional current flow f. Direct current (DC) g. Alternating current (AC) h. Ideal source i. Real source Conductors Conductors are materials with electrons that are loosely bound to their atoms, or materials that permit free motion of a large number of electrons. Atoms with only one valence electron, such as copper, silver, and gold, are examples of good conductors. Most metals are good conductors. Insulators Insulators, or nonconductors, are materials with electrons that are tightly bound to their atoms and require large amounts of energy to free them from the influence of the nucleus. The atoms of good insulators have their valence shells filled with eight electrons, which means they are more than half filled. Any energy applied to such an atom will be distributed among a relatively large number of electrons. Examples of insulators are rubber, plastics, glass, and dry wood. Resistors Resistors are made of materials that conduct electricity, but offer opposition to current flow. These types of materials are also called semiconductors because they are neither good conductors nor good insulators. Semiconductors have more than one or two electrons in their valence shells, but less than seven or eight. Examples of semiconductors are carbon, silicon, germanium, tin, and lead. Each has four valence electrons. Rev. 0 Page 9 ES-01