INVERSELYInverted or reversed in position or relationship .
INVERTTo change a physical or logical state to its opposite state .
INVERTERA 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 .
IONAn electrically charged atom or group of atoms. Negative ions have an excess of electrons; positive
ions have a deficiency of electrons .
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  .
IONIZATION POINTThe potential required to ionize the gas of a gas-filled tube. Sometimes called
firing potential .
IONIZETo 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 .
IONOSPHEREThe 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 .
IONOSPHERIC STORMSDisturbances in the earth's magnetic field that make communications
practical only at lower frequencies .
IRISA metal plate with an opening through which electromagnetic waves may pass. Used as an
impedance-matching device in waveguides .
I2R LOSSSee COPPER LOSSES .
ISOLATIONThe prevention of unwanted interaction or leakage between components .
ISOMETRIC DIAGRAMA diagram showing the outline of a ship, aircraft, or equipment and the
location of equipment and cable runs .
ISOTROPIC RADIATIONThe radiation of energy equally in all directions .
JUNCTION(1) The connection between two or more conductors. (2) The contact between two dissimilar
metals or materials, as in a thermocouple .
JUNCTION BOXA 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 .
JUNCTION DIODEA two-terminal device containing a single crystal of semiconducting material that
ranges from P-type at one terminal to N-type at the other .
JUNCTION TRANSISTORA 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 .
KEEP-ALIVE CURRENTSee KEEP-ALIVE VOLTAGE .