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FERRITE—A powdered and compressed ferric oxide material that has both magnetic properties and light
resistance to current flow [11].
FERRITE SWITCH—A ferrite device that blocks the flow of energy through a waveguide by rotating the
electric field 90 degrees. The rotated energy is then reflected or absorbed [11].
FERROMAGNETIC MATERIAL—A highly magnetic material, such as iron, cobalt, nickel, or their
alloys [1].
FERRULES—The cylindrical metallic ends of a cartridge fuse [3].
FIBER OPTICS—Conductors or optical waveguides that readily pass light [17].
FIBROUS BRAID—An outer covering used to protect a conductor's insulating material. Commonly made
from cotton, linen, silk, rayon, or fiberglass [4].
FIDELITY—(1) The faithful reproduction of a signal. (2) The accuracy with which a system reproduces a
signal at its output that faithfully maintains the essential characteristics of the input signal [7] [8] [12]
[17].
FIELD—The electromagnet which furnishes the magnetic field that interacts with the armature in motors
and generators [5].
FIELD-EFFECT TRANSISTOR (FET)—A transistor consisting of a source, a gate, and a drain. Current
flow is controlled by the transverse electric field under the gate [7].
FIELD EXCITATION—The creation of a steady magnetic field within the field windings by the
application of a dc voltage either from the generator itself or from an external source [5].
FIELD OF FORCE—A term used to describe the total force exerted by an action-at-a-distance
phenomenon such as gravity upon matter, electric charges acting upon electric charges, and magnetic
forces acting upon other magnets or magnetic materials [1].
FILAMENT—The cathode of a thermionic tube, usually a wire or ribbon, which is heated by current
passing through it [6].
FILM ICs—Conductive or nonconductive material deposited on a glass or ceramic substrate. Used for
passive circuit components, resistors, and capacitors [14].
FILTER—A selective network of resistors, capacitors, and inductors that offers comparatively little
opposition to certain frequencies, while blocking or attenuating other frequencies [6] [9].
FINAL POWER AMPLIFIER (FPA)—The final stage of amplification in a transmitter [12].
FIRST DETECTOR—See MIXER [18].
FIXED BIAS—A constant value of bias voltage [6] [7] [13].
FIXED RESISTOR—A resistor having a definite resistance value that cannot be adjusted [1].
FIXED SPARK GAP—A device used to discharge the pulse-forming network. A trigger pulse ionizes the
air between two contacts to initiate the discharge [12].
FLAT LINE—A transmission line that has no standing waves. This line requires no special timing devices
to transfer maximum power [10].
