Neets Master Glossary

1-37 INVERSELY—Inverted or reversed in position or relationship [1]. INVERT—To change a physical or logical state to its opposite state [13]. INVERTER—A circuit with one input and one output. Its function is to invert or reverse the input. When the input is high, the output is low, and vice versa. The inverter is sometimes called a NOT circuit, since it produces the reverse of the input [13]. ION—An electrically charged atom or group of atoms. Negative ions have an excess of electrons; positive ions have a deficiency of electrons [1]. IONIZATION—(1) The process of producing ions. (2) The electrically charged particles produced by high- energy radiation, such as light or ultraviolet rays, or by the collision of particles during thermal agitation [6] [10]. IONIZATION POINT—The potential required to ionize the gas of a gas-filled tube. Sometimes called firing potential [6]. IONIZE—To make an atom or molecule of an element lose an electron, as by X-ray bombardment, and thus be converted into a positive ion. The free electron may attach itself to a neutral atom or molecule to form a negative ion [1]. IONOSPHERE—The most important region of the atmosphere extending from 31 miles to 250 miles above sea level. Contains four cloud-like layers that affect radio waves [10]. IONOSPHERIC STORMS—Disturbances in the earth's magnetic field that make communications practical only at lower frequencies [10]. IRIS—A metal plate with an opening through which electromagnetic waves may pass. Used as an impedance-matching device in waveguides [11]. I²R LOSS—See COPPER LOSSES [11]. ISOLATION—The prevention of unwanted interaction or leakage between components [14]. ISOMETRIC DIAGRAM—A diagram showing the outline of a ship, aircraft, or equipment and the location of equipment and cable runs [4]. ISOTROPIC RADIATION—The radiation of energy equally in all directions [10]. JUNCTION—(1) The connection between two or more conductors. (2) The contact between two dissimilar metals or materials, as in a thermocouple [1]. JUNCTION BOX—A box with a cover that serves the purpose of joining different runs of wire or cable and provides space for the connection and branching of the enclosed conductors [4]. JUNCTION DIODE—A two-terminal device containing a single crystal of semiconducting material that ranges from P-type at one terminal to N-type at the other [7]. JUNCTION TRANSISTOR—A bipolar transistor constructed from interacting PN junctions. The term is used to distinguish junction transistors from other types, such as field-effect and point-contact [7]. KEEP-ALIVE CURRENT—See KEEP-ALIVE VOLTAGE [18].