HYSTERESISThe time lag of the magnetic flux in a magnetic material behind the magnetizing force
producing it. Caused by the molecular friction of the molecules trying to align themselves with the
magnetic force applied to the material .
HYSTERESIS LOSSThe power loss in an iron-core transformer or other alternating-current device as a
result of magnetic hysteresis .
IC SYNCHROSObsolete synchros with reverse rotation and limited torque capabilities .
IDEMPOTENT LAWIn Boolean algebra, combining a quantity with itself either by logical addition or
logical multiplication will result in a logical sum or product that is the equivalent of the quantity (for
example, A + A = A; A
A = A) .
IDENTITY LAWIn Boolean algebra, the law which states that any expression is equal to itself (for
IDLER FREQUENCYIn a parametric amplifier, the difference between the input signal and the pump
signal frequency. Also called the LOWER-SIDEBAND FREQUENCY .
IF AMPLIFIERUsually a narrow-bandwidth IF amplifier that is tuned to one of the output frequencies
produced by the mixer .
IGFETAny field-effect transistor that has an insulated gate .
IMAGE FREQUENCYAn undesired frequency capable of producing the desired frequency through
IMPEDANCEThe total opposition offered to the flow of an alternating current. It may consist of any
combination of resistance, inductive reactance, and capacitive reactance. The symbol for impedance is
Z  .
IMPLOSIONThe inward bursting of a CRT because of high vacuum. The opposite of explosion .
INCIDENT WAVE(1) The wave that strikes the surface of a medium. (2) The wave that travels from the
sending end to the receiving end of a transmission line .
IN-CIRCUIT METERA meter permanently installed in a circuit; used to monitor circuit operation .
INCOHERENTRefers to radiation on a broad band of frequencies .
INDEX OF REFRACTIONThe degree of bending of an RF wave when passing from one medium to
INDICATOREquipment in radar that provides a visual presentation of target position information .
INDIRECTLY HEATED CATHODESame as the directly heated cathode with one exception: The hot
filament raises the temperature of the sleeve around the filament; the sleeve then becomes the electron
INDUCED-CHANNEL MOSFETA MOSFET in which there is no actual channel between the source
and the drain. This MOSFET is constructed by making the channel of the same type of material as the