FERRITEA powdered and compressed ferric oxide material that has both magnetic properties and light
resistance to current flow .
FERRITE SWITCHA 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 .
FERROMAGNETIC MATERIALA highly magnetic material, such as iron, cobalt, nickel, or their
FERRULESThe cylindrical metallic ends of a cartridge fuse .
FIBER OPTICSConductors or optical waveguides that readily pass light .
FIBROUS BRAIDAn outer covering used to protect a conductor's insulating material. Commonly made
from cotton, linen, silk, rayon, or fiberglass .
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   
FIELDThe electromagnet which furnishes the magnetic field that interacts with the armature in motors
and generators .
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 .
FIELD EXCITATIONThe 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 .
FIELD OF FORCEA 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 .
FILAMENTThe cathode of a thermionic tube, usually a wire or ribbon, which is heated by current
passing through it .
FILM ICsConductive or nonconductive material deposited on a glass or ceramic substrate. Used for
passive circuit components, resistors, and capacitors .
FILTERA selective network of resistors, capacitors, and inductors that offers comparatively little
opposition to certain frequencies, while blocking or attenuating other frequencies  .
FINAL POWER AMPLIFIER (FPA)The final stage of amplification in a transmitter .
FIRST DETECTORSee MIXER .
FIXED BIASA constant value of bias voltage   .
FIXED RESISTORA resistor having a definite resistance value that cannot be adjusted .
FIXED SPARK GAPA device used to discharge the pulse-forming network. A trigger pulse ionizes the
air between two contacts to initiate the discharge .
FLAT LINEA transmission line that has no standing waves. This line requires no special timing devices
to transfer maximum power .