.WAFER - A slice of semiconductor material upon which monolithic ICs are
produced .
WAFER SWITCH - A rotary switch in which the contacts are arranged on
levels. Each level (wafer) is electrically independent but mechanically connected by the
shaft of the switch .
WASHOUT - (1) A hard-coated head whose magnetic core material has a much
higher wear rate than the coating. (2) The radius of curvature of the core material will
be larger than the surrounding coating of the softer material, which could even be
undercut, possibly causing an increase in the head-to-tape separation. (3) Also called
undercut.
WATT - The unit of electrical power that is the product of voltage and
current .
WATTAGE RATING - A rating expressing the maximum power that a device can
safely handle .
WATT-HOUR - A practical unit of electrical energy equal to one watt of
power for one hour .
WATT-HOUR METER - A meter used to measure electrical energy .
WATTMETER - A meter used to measure electrical power .
WAVE ANTENNA - Same as BEVERAGE ANTENNA .
WAVEFORM - The shape of the wave obtained when instantaneous values of an
ac quantity are plotted against time in rectangular coordinates .
WAVEFORM ANALYSIS - Observation displays of voltage and current variations
with respect to time or by harmonic analysis of complex signals .
WAVEFRONT - A small section of an expanding sphere of electromagnetic
radiation that is perpendicular to the direction of travel of the energy .
WAVEGUIDE - A rectangular, circular, or elliptical metal pipe designed to
transport electromagnetic waves through its interior .
WAVEGUIDE DUPLEXER - TR and atr tubes housed in a resonant cavity attached
to a waveguide system.
WAVEGUIDE MODE OF OPERATION - Any particular field configuration in a
waveguide that satisfies the boundary conditions. Usually divided into two broad types:
the transverse electric (TE) and the transverse magnetic (TM) modes .
WAVEGUIDE POST - A rod of conductive material used as impedance changing
devices in waveguides .
WAVEGUIDE SCREW - A screw that projects into a waveguide for the purpose
of changing the impedance .
WAVELENGTH - The distance, usually expressed in meters, traveled by a wave
during the time interval of one complete cycle. It is equal to the velocity divided by the
frequency .
WAVEMETERS - (1) Calibrated resonant circuits that are used to measure
frequency. (2) An instrument for measuring the wavelength of an rf wave.
WAVE MOTION - A recurring disturbance advancing through space with or
without the use of a physical medium .
WAVE TRAIN - A continuous series of waves with the same amplitude and
wavelength .
WAVE WINDING - An armature winding in which the two ends of each coil are
connected to commutator segments separated by the distance between poles .
WAVINESS - (1) A non-flat head's top surface perpendicular to the tape
motion due to different wear rates in top surface materials. The harder material will be
up. The head core is usually the harder material; therefore, there will be increased
head-to-tape contact pressure at the cost of tape life. (2) Can occur during break-in or
field use.
WEAR ABILITY - (See durability.)
WEAR PRODUCT - Any material that is detached from the tape during use.
WEAR TEST - (See durability.)
WEBER'S THEORY - A theory of magnetism which assumes that all magnetic
material is composed of many tiny magnets. A piece of magnetic material that is magnetized
has all of the tiny magnets aligned so that the north pole of each magnet points in one
direction .
WHEATSTONE BRIDGE - An ac bridge circuit used to measure unknown values of
resistance, inductance, or capacitance .
WIDE AREA NETWORK - A network that usually covers large geographical
areas. Communications between stations or terminals usually occur using standard telephone
lines or microwave relays.
WIDE-BAND AMPLIFIER - An amplifier designed to pass an extremely wide band
of frequencies, such as a video amplifier .
WIND - The way in which tape is wound onto a reel. An A-wind is one in
which the tape is wound so that the coated surface faces toward the hub.
WINDER/CLEANER - A device that winds and cleans magnetic tape to restore
it to a near-new condition, providing the tape has not been physically damaged.
WINDOW - See SLOT .
WIRE - An insulated conductor, with low resistance to current flow, that
is either solid or stranded .
WIRING DIAGRAM - A diagram that shows the connections of an equipment or
its component devices or parts. It may cover internal or external connections, or both,
and contains such detail as is needed to make or trace connections that are involved .
WOBBLE FREQUENCY - The frequency at which an electron wobbles on its axis
under the influence of an external magnetic field of a given strength .
WORD, COMPUTER - A group of related bytes treated as a single addressable
unit or entity in computer memory.
WORDS-PER-MINUTE - An approximate rate of speed. It means the number of
five letter words with a space between them that can be transmitted or received in a
one-minute period .
WORK - The product of force and motion .
WORKING VOLTAGE - The maximum voltage that a capacitor may operate at
without the risk of damage .
WOW AND FLUTTER - (1) The changes in signal-output frequency caused by
tape-speed variations occurring at relatively low and relative high rates, respectively.
(2) Wow is no longer used, but is incorporated into the flutter measurement.
WRITE FEEDTHROUGH - (1) The magnetic coupling from the write track to a
read track in the read/write head. (2) Also called crossfeed and crosstalk.
WYE (Y) - A 3-phase connection in which one end of each phase winding is
connected to a common point. Each free end is connected to a separate phase wire. The
diagram of this connection often resembles the letter Y .
