INSTANTANEOUS AMPLITUDEThe amplitude at any given point along a sine wave at a specific
instant in time .
INSTANTANEOUS AUTOMATIC GAIN CONTROL (IAGC)A circuit that can vary the gain of the
radar receiver with each input pulse to maintain a nearly constant output peak amplitude .
INSTANTANEOUS VALUEThe magnitude at any particular instant when a value is continually varying
with respect to time .
INSULATIONA material used to prevent the leakage of electricity from a conductor and to provide
mechanical spacing or support as protection against accidental contact with the conductor  .
INSULATION RESISTANCEThe resistance offered by an insulating material to current leakage .
INSULATOR(1) Material of such low conductivity that the flow of current through it can usually be
neglected. (2) A device having high electrical resistance; used for supporting or separating conductors
so as to prevent undesired flow of current from the conductors to other objects .
INTEGRATED CIRCUIT (IC)(1) A circuit in which many elements are fabricated and interconnected
by a single process (into a single chip), as opposed to a "nonintegrated" circuit in which the transistors,
diodes, resistors, and other components are fabricated separately and then assembled . (2) Elements
inseparably associated and formed on or within a single substrate .
INTELLIGENCEIn communications any signal that conveys information (voice, teletypewriter,
INTENSITY (OF SOUND)The measurement of the amplitude of sound energy. Generally synonymous
with loudness .
INTERACTION SPACEThe region in an electron tube where the electrons interact with an alternating
electromagnetic field .
INTERCEPTThe point where two lines drawn on a graph cross each other .
INTERELECTRODE CAPACITANCEThe capacitance between the electrodes of an electron tube 
INTERFERENCEAny disturbance that produces an undesirable response or degrades a signal .
INTERMEDIATE FREQUENCY (IF)A lower frequency to which an RF echo is converted for ease of
INTERMEDIATE-LEVEL MAINTENANCE (SM&R Code I)Direct support and technical assistance
to user organizations. Tenders and shore-based repair facilities .
INTERMEDIATE POWER AMPLIFIERThe amplifier between the oscillator and final power
INTERPOLESSmall auxiliary poles, placed between main field poles, whose magnetic field opposes the
armature field and cancels armature reaction. Interpoles accomplish the same thing as compensating
INTERSECTION LAWIn Boolean algebra, the law which states that if one input to an AND gate is
already TRUE, then the output will depend upon the state of the other inputs only .