. 40
( 42)


tem having a bandpass capable of transferring a memory is the fact that it can easily be erased if
human voice with reasonable intelligibility. See desired. Compare NONVOLATILE MEMORY.
voice-grade channel 1. A telephone line and at- volatile store See VOLATILE MEMORY.
tendant equipment suitable for the transmission Voldicon A form of semiconductor logic device
of speech and certain other information, such as used for analysis of analog signals. Trade name of
control signals, digital data, etc. 2. In a radiotele- Adage, Inc.
phone transmitter, a speech amplifier-modulator volt Abbreviation, V. The basic practical unit of dif-
channel suitable only for voice frequencies. ference of potential (i.e., of electrical pressure); 1
voice-operated control Abbreviation, vox. Per- volt is the difference of potential produced across
taining to a device (such as a relay, automatic a resistance of 1 ohm by a current of 1 ampere.
modulation control, transmit-receive switch, etc.) Also see KILOVOLT, MEGAVOLT, MICROVOLT,
that is actuated when the operator speaks into a MILLIVOLT, NANOVOLT, and PICOVOLT.
microphone. Volta effect See VOLTA™S PRINCIPLE.
voice-operated device, anti-sing See VODA. voltage Symbols, E, e, V, v. Electromotive force, or
voice-operated gain-adjusting device See VO- difference of potential; E = IR, where I is current
GAD. and R is resistance. Also see VOLT.
voice-operated loss control and suppressor In voltage-actuated device An electronic device,
wire telephony, a device that switches the loss such as a field-effect transistor, that amplifies a
from the transmitting line to the receiving line voltage signal or is controlled by a voltage, and
when the subscriber speaks, and vice versa. draws virtually no signal current or control cur-
voice-over The simultaneous recording of a human rent. The opposite is a current-actuated device,
voice (such as that of a narrator) along with other such as a bipolar transistor.
sounds (such as music, children playing, wind in voltage amplification 1. Abbreviation, Av. Amplifi-
trees, ocean waves, chirping birds, etc.). The voice cation of an input-signal voltage to provide a
is generally louder than the other sounds. higher output-signal voltage. 2. Abbreviation, Av.
voice print A graphic recording of the speech fre- The signal increase (Vout/Vin) resulting from this
quencies produced by an individual and used as process. Also called voltage gain.
a means of identifying that individual. voltage-amplification device A low-current de-
voice-recognition device See SPEECH RECOG- vice designed especially for voltage amplification.
NIZER. It provides little or no power amplification.
voice security In voice communications system, voltage amplifier An amplifier operated primarily
the use of encryption and decryption, usually in to increase a signal voltage. Compare CURRENT
the form of digital algorithms, to “scramble” AMPLIFIER and POWER AMPLIFIER.
speech at the source and “unscramble” it at the voltage at peak torque Symbol, Vp. For a torque
destination. motor operated at 25°C, the voltage required to
voice-stress analyzer Abbreviation, VSA. An in- produce peak torque at standstill.
strument that samples the spoken voice and pro- voltage attenuation 1. The reduction in voltage at
duces a display from which the relative amount of a given point in a circuit. 2. For a device, the ra-
stress experienced by the speaker can be deter- tio of input voltage to output voltage when the
mined, and from which, in turn, probable truth output voltage is the lower quantity.
or falsity of statements or answers can be in- voltage-balance relay A relay actuated by a volt-
ferred. age differential.
voice synthesis device See SPEECH SYNTHE- voltage breakdown See BREAKDOWN VOLTAGE.
SIZER. voltage-breakdown test 1. A test in which the
void space See VACUUM. measured voltage applied to an insulating
vol Abbreviation of VOLUME. material is continuously increased until the
732 voltage-breakdown test • voltage divider

breakdown point is reached. 2. A test in which type that employs a varactor diode in the capaci-
the measured reverse voltage applied to a semi- tive portion of the tuned circuit. The varactor is
conductor junction is continuously increased un- placed in series or parallel with the tuning capac-
til the reverse breakdown point is reached (see itor and is isolated for direct current by blocking
AVALANCHE BREAKDOWN). capacitors. The frequency can be adjusted, within
voltage burden The voltage drop across a CUR- certain limits, by nonmechanical means. The sig-
RENT SHUNT. nal can also be frequency modulated by applying
voltage calibrator A device used to calibrate, in the modulating voltage across the varactor.
terms of voltage, a meter scale, oscilloscope voltage-controlled resistor See VOLTAGE-DE-
screen, graphic-recorder chart, etc. PENDENT RESISTOR.
voltage-capacitance curve A plot depicting the voltage corrector See VOLTAGE REGULATOR.
variation of capacitance with applied voltage for a voltage crest See VOLTAGE PEAK.
voltage-variable capacitor. For a varactor (vari- voltage-current characteristic See VOLTAGE-
able-capacitance diode), capacitance varies in- CURRENT CURVE.
versely with reverse direct-current voltage. voltage-current crossover The point at which a
voltage coefficient A figure that shows the extent voltage-regulated supply becomes a current-
to which a quantity drifts under the influence of regulated supply.
voltage. It is generally expressed in percent per voltage-current curve For a circuit or device, the
volt or in parts per million per volt (ppm/V). plot of the interrelationship of current and volt-
voltage coefficient of capacitance For a voltage- age, with voltage as the independent variable.
dependent capacitor, the capacitance change per voltage-current feedback See CURRENT-VOLT-
unit change in applied voltage. AGE FEEDBACK.
voltage coefficient of resistance For a voltage- voltage decay The exponential decrease of voltage
dependent resistor, the resistance change per across a discharging capacitor. Also see EXPO-
unit change in applied voltage. NENTIAL DECREASE.
voltage coil See POTENTIAL COIL. voltage-dependent capacitor A capacitor (such as
voltage comparator A device for comparing (usu- a varactor) whose capacitance varies with applied
ally only two) voltages. The various types range voltage.
from simple, manually balanced potentiometers voltage-dependent resistor A nonlinear resistor
to analog or digital devices that automatically whose value varies inversely with the voltage drop
compare the applied voltages and provide a direct across it. Also called varistor.
readout of either their difference or the percent of voltage detector A circuit or device that delivers
unbalance. an output voltage only when the input voltage is
voltage control 1. A component or circuit that al- of a prescribed value. Compare VOLTAGE DIS-
lows the adjustment of the output voltage of a CRIMINATOR.
power supply within a given range. 2. The adjust- voltage-determined property A property (capaci-
ment of the output voltage of a power supply to tance, current, frequency, or resistance) whose
optimize the performance of a circuit connected magnitude depends on the value of an applied
to the supply. 3. Any form of circuit control that voltage. See, for example, VOLTAGE-DEPENDENT
is accomplished by the adjustment of the voltage CAPACITOR, VOLTAGE-DEPENDENT RESISTOR,
at a given circuit point. and VOLTAGE-CONTROLLED OSCILLATOR.
voltage-controlled amplifier Abbreviation, VCA. voltage differential Symbol, dE or dV. An in-
An amplifier in which gain is controlled by means finitesimal change in voltage. Compare VOLTAGE
of a voltage applied to a control terminal. INCREMENT.
voltage-controlled attenuator An attenuator cir- voltage-directional relay 1. A relay that is actu-
cuit in which a transistor serves as a voltage- ated when voltage exceeds a certain value in a
variable resistor. The output resistance of the given direction. 2. A relay that closes only when
transistor varies inversely with the direct-current the applied voltage is in a specific direction.
bias voltage applied to the input electrode (base, voltage discriminator A circuit or device whose
emitter, or gate). output voltage is zero when the input voltage is of
voltage-controlled capacitor See VOLTAGE- a prescribed value. When the input voltage is
DEPENDENT CAPACITOR. greater than this value, the output is positive;
voltage-controlled crystal oscillator Abbrevia- when it is less, the output is negative.
tion, VCCO or VCXO. A voltage-controlled oscilla- voltage distribution 1. The delivery of operating
tor of the crystal-stabilized type. voltage throughout a circuit (e.g., high and low
voltage-controlled generator Abbreviation, VCG. direct-current voltages in the various stages of a
Any signal-generating device whose output fre- control circuit). 2. Sometimes, the distribution of
quency is varied by changing one of the direct- electrical energy (“power” distribution).
current operating voltages of the device. voltage divider A resistive or capacitive poten-
voltage-controlled oscillator Abbreviation, VCO. tiometer or network used to divide an applied
An oscillator of the inductance-capacitance (LC) voltage by a desired amount.
voltage doubler • voltage peak

Edc = 2(1.41)Erms See, for example, VOLTAGE-TO-SHAFT-POSI-
voltage inverter A circuit or device whose voltage
output has the sign opposite that of the input
voltage. The device might or might not provide
Input C1 amplification.
+ voltage jump 1. An upward transient in voltage.
Output 2. In a glow-discharge tube, a sudden break or
_ (Edc) increase in voltage drop across the tube.
voltage lag The condition in which voltage changes
C2 occur after corresponding current changes. Com-
voltage lead The condition in which voltage
changes precede corresponding current changes.
voltage doubler Compare CURRENT LEAD and VOLTAGE LAG.
voltage level 1. A prescribed reference value of
voltage (e.g., the black level in a television picture
signal). 2. The discrete value of a steady voltage,
voltage doubler A power-supply circuit that sup-
or the average value of a fluctuating voltage, as
plies a direct-current output voltage of about
observed or measured in a circuit.
twice the peak value of the alternating-current in-
voltage limit The maximum or minimum level in a
put voltage.
voltage range.
voltage drift See DRIFT VOLTAGE.
voltage loop In a standing-wave system, such as
voltage drop Abbreviation, VD. The voltage (E) set
an antenna or transmission line, a maximum-
up across a resistance (R) carrying a current (I);
voltage point. Compare VOLTAGE NODE.
E = IR. For alternating current, reactance X and
voltage loss 1. Reduction of a voltage across a
impedance Z can be substituted for resistance,
load, occurring because of a series resistance.
where applicable.
2. The ratio, in decibels, between the input voltage
voltage-equalizing resistors In a power-supply fil-
to a transmission line and the output voltage at
ter, resistors connected across each capacitor in
the load end of the line, assuming that the
a string of electrolytics connected in series to
impedance is the same at both points.
withstand a high voltage. The resistors protect
voltage maximum See VOLTAGE PEAK.
the capacitors by equalizing the voltage across
voltage minimum See VOLTAGE TROUGH.
voltage-mode switching circuit A resistor-tran-
voltage-fed antenna An antenna in which the
sistor-logic (RTL) NAND or NOR circuit in which
feeder is attached to the radiator at a voltage loop
(in the off state) the transistor is cut off by the VBB
(current node). Compare CURRENT-FED AN-
bias voltage. The output is then approximately
equal to the collector supply voltage, VCC. The
voltage feed The delivery of voltage to a device or
proper combination of input pulses overrides the
circuit at a point where voltage, rather than cur-
cutoff bias, and the transistor switches on. The
rent, is dominant. Compare CURRENT FEED.
output then drops to a level equal to VCC minus
voltage feedback A feedback signal consisting of
the voltage drop across the external collector re-
voltage fed from the output to the input circuit of
an amplifier or other device. Compare CURRENT
voltage multiplier A special type of rectifier circuit
that delivers a direct-current output voltage that
is a multiple of the peak value of the alternating-
voltage-frequency transducer 1. A device whose
current input voltage, thus affording voltage step-
output voltage is a function of the frequency of a
up without a transformer. See, for example,
signal at the input. 2. A device whose output
frequency is a function of the voltage at the
voltage node In a standing-wave system, such as
an antenna or transmission line, a minimum-
voltage generator See VOLTAGE SUPPLY.
voltage point. Compare VOLTAGE LOOP.
voltage gradient The voltage per unit length along
voltage of self-induction The voltage drop across
a defined path.
an inductor, resulting from the flow of alternating
voltage increment A change in voltage repre-
current through the inductor; it is caused by self-
sented by E2 “ E1, where E2 and E1 are the volt-
ages at two defined points on a curve, and the
voltage peak The highest value attained by a volt-
difference is finite (nonzero). Compare VOLTAGE
age during an excursion. Also called voltage crest
or voltage maximum. Compare VOLTAGE
voltage input encoder An analog-to-digital en-
coder for which the input is an analog voltage.
734 voltage-power directional relay • voltage-sensitive bridge

D2 voltage-regulated supply See CONSTANT-VOLT-
voltage-regulating transformer A special trans-
former in which a resonant circuit and core satu-
ac ration (see SATURATED OPERATION, 1) are used
D1 to provide a constant output voltage.
(Erms) dc
+ voltage regulation The stabilization of a voltage
Output against fluctuations in source or load.
(Edc) voltage-regulation constant Symbol, Kv. For a
voltage-regulated power supply, the ratio
dEL/dEi, where dEi is a change in input voltage,
and dEL is the corresponding change in load volt-
C2 D4 age.
voltage regulator A circuit or device that holds an
Edc = 4(1.41)Erms output voltage constant during variations in the
output load or input voltage.
voltage-regulator diode See ZENER-DIODE
voltage quadrupler
voltage-regulator transformer See VOLTAGE-
voltage-power directional relay A relay system in
voltage relay A relay or relay circuit that is actu-
which two circuits are connected when their volt-
ated by a discrete voltage, rather than by current
age difference exceeds a predetermined value in
or power.
one direction, and are disconnected when the
voltage-responsive device See VOLTAGE-ACTU-
voltage in the opposite direction exceeds a prede-
termined level.
voltage rise The normal condition in a series-
voltage quadrupler A special rectifier circuit that
resonant circuit, in which the voltage across the
supplies a direct-current output voltage of ap-
coil or capacitor is higher than the voltage applied
proximately four times the peak alternating-
to the circuit.
current input voltage.
voltage saturation In a current-actuated device,
voltage quintupler See QUINTUPLER, 1.
such as a bipolar transistor, the situation in
voltage-range multiplier 1. A multiplier resistor
which an increase in current provides no increase
(see VOLTMETER MULTIPLIER) connected in se-
in voltage drop beyond a certain point (the satu-
ries with a voltmeter that has an internal multi-
ration point).
plier, to increase the range of the instrument.
voltage-sensitive bridge A bridge having a nonlin-
2. For an alternating-current voltmeter, an input
ear element (such as a voltage-dependent resis-
amplifier used to increase the sensitivity of the in-
tor) as one of the arms. Because of this element,
the bridge can be balanced (with a given set of
voltage rating 1. For a circuit or device, the rec-
other arms) at only one value of applied voltage.
ommended maximum voltage that can be ap-
At lower voltages, the bridge becomes unbalanced
plied, or the recommended working voltage, as
in one direction; at higher voltage, in the opposite
specified. 2. For a generator, the specified output
voltage ratio The quotient of the voltages, E1/E2,
at two specific points in a circuit, device, or sys-
tem. Examples: ratio of input voltage to output Nonlinear element (varistor,
voltage and ratio of primary voltage to secondary semiconductor diode, thermistor,
voltage. tungsten-filament lamp, etc.)
voltage-ratio box See VOLT BOX.
voltage reference See STANDARD CELL and
voltage-reference cell See STANDARD CELL.
voltage-reference diode A Zener diode biased
into its Zener region. The voltage drop across the Adjustable
diode is comparatively constant. Under proper voltage Output
conditions, it can be used for reference input
purposes. Also see ZENER-DIODE VOLTAGE
voltage reflection coefficient In a reflected-wave
situation, the ratio Er/Ei, where Ei is the field-
strength voltage of the incident wave, and Er is
voltage-sensitive bridge
the field-strength voltage of the reflected wave.
voltage-sensitive capacitor • voltaic pile

C1 D1
voltage-sensitive capacitor See VOLTAGE-
voltage-sensitive resistor See VOLTAGE-DEPEN-
voltage sensitivity 1. Particular responsiveness of Input D2 C2 dc
a circuit or device to voltage, rather than current (Erms)
or power. See, for example, VOLTAGE-DEPEN-
voltage-spectrum function The voltage-vs.-
frequency curve at the output of a circuit or
Edc = 3(1.41)Erms
voltage-stabilized supply See CONSTANT-VOL-
voltage stabilizer See VOLTAGE REGULATOR. voltage tripler
voltage-stabilizing diode See ZENER-DIODE
voltage standard A device that delivers a voltage of voltage tuning A method of adjusting the fre-
accuracy and stability so that it can be used to quency of an oscillator or resonant circuit by
calibrate other voltage generators and test instru- means of a variable, direct-current voltage.
ments. See, for example, STANDARD CELL and voltage-tunable magnetron A magnetron oscilla-
ZENER-DIODE VOLTAGE REFERENCE. tor in which the output frequency is varied by ad-
voltage standing-wave ratio Abbreviation, VSWR. justing the direct-current voltage on the tube.
In a standing-wave system, the ratio of the maxi- voltage-tunable oscillator See VOLTAGE-
mum voltage to the minimum voltage. CONTROLLED OSCILLATOR.
voltage supply A power supply whose usable out- voltage-turns ratio The turns ratio of a trans-
put is voltage, rather than current or power. former, indicated by the ratio of primary voltage
When such a supply is not voltage-regulated, it to secondary voltage, or vice-versa.
can only be used reliably with a very light load. voltage-type telemetry Telemetry based upon the
voltage to chassis In electronic equipment variation of a single voltage in sympathy with the
mounted on a metal chassis, the voltage between changes in a sensed phenomenon.
the chassis and a given point in the circuit. voltage-variable capacitor 1. A specially pro-
voltage-to-frequency converter A device or cir- cessed semiconductor diode of which the voltage-
cuit that delivers an output frequency propor- variable capacitance of the junction is utilized.
tional to an input voltage (usually direct current). Also called VARACTOR. 2. A capacitor having a
Compare FREQUENCY-TO-VOLTAGE CON- specially processed nonlinear dielectric, such as
VERTER. barium strontium titanate, whose capacitance
voltage to ground 1. In a circuit, the voltage mea- varies inversely with the applied direct-current
sured between a given point and the ground bias voltage.
point. 2. The voltage measured between the earth voltage-variable resistor See VOLTAGE-DEPEN-
and a line or piece of equipment. DENT RESISTOR.
voltage to panel In electronic equipment mounted voltage vector In a vector diagram, a vector show-
on a metal panel, the voltage between the panel ing the magnitude and phase of a voltage. Com-
and a given point in the circuit. pare CURRENT VECTOR.
voltage-to-shaft-position encoder An encoder for voltaic Pertaining to chemically produced direct
which the output is the rotation of a motor shaft current. Sometimes interchangeable with gal-
over an arc proportional to an input voltage. vanic.
voltage transformer 1. A transformer used voltaic cell For the generation of a direct-current
primarily to supply voltage with little or no voltage, a primary cell consisting of two elec-
current. 2. A small step-up transformer for in- trodes made of different metals and immersed in
creasing the sensitivity of an alternating-current an electrolyte. Also called GALVANIC CELL. Also
voltage tripler A rectifier circuit that, without a voltaic couple A pair of dissimilar metals (or other
transformer, supplies a direct-current output substances) that generate a direct-current volt-
voltage of approximately three times the peak age when they contact an electrolyte.
value of the alternating-current input voltage. voltaic pile A rudimentary primary battery con-
voltage trough The lowest value reached by a volt- sisting of a series of disks made of two different
age during an excursion. Compare VOLTAGE metals, stacked alternately with electrolyte-
PEAK. soaked cloth or paper disks.
736 voltaic series • volume-limiting amplifier

voltaic series See ELECTROMOTIVE SERIES. volt-milliammeter A combination meter for mea-
voltameter An electrolytic cell for determining the suring volts and milliamperes.
value of an unknown current, or of an unknown volt-ohm-ammeter A multimeter for measuring
quantity of electricity, from the weight of metal voltage, resistance, and current (in amperes).
deposited out of an electrolyte onto the cathode volt-ohmmeter A combination meter for measur-
by the passage of current over an accurately ing voltage and resistance.
timed interval. volt-ohm-milliammeter Abbreviation VOM. A
volt-ammeter A combination meter for measuring multimeter for measuring voltage, resistance,
electrical voltages and currents. and current (in milliamperes and microamperes).
volt-ampere Symbol, VA. Unit, watt. The simple voltsensor See VOLTAGE DETECTOR.
product of voltage and current in volts and am- volts per meter Abbreviation, V/m or Vpm. The
peres, yielding the true power in a direct-current unit of electric field strength.
circuit and the apparent power in an alternating- volume 1. Intensity of sound. Also called LOUD-
current circuit. Also see APPARENT POWER and NESS. 2. A circumscribed portion of space, either
TRUE POWER. imaginary or actually occupied, and described by
volt-ampere-hour meter See VAR-HOUR METER. three dimensions (e.g., sphere, ellipsoid, cube,
volt-ampere meter See VAR METER. pyramid, etc.). 3. In a computer system, a unit of
volt-amperes reactive Abbreviation, VAR. The magnetic storage medium (e.g., a diskette).

product of volts and amperes for a purely reactive volume compression The automatic reduction of
circuit. This product does not produce the true the gain of an audio amplifier. The process differs

power because the power factor is neglected; it from clipping (which “slices off” the tops of waves)
produces only the apparent power. A true reac- in that compression (ideally) reduces the ampli-
tance absorbs power during one half-cycle of al- tude while preserving the waveform. Compare
ternating current, and returns it to the generator VOLUME EXPANSION.
during the next half-cycle. volume compressor A circuit or device (such as an
Volta™s law See VOLTA™S PRINCIPLE. automatic-gain-control amplifier) for achieving vol-
Volta™s pile See VOLTAIC PILE. ume compression. Compare VOLUME EXPANDER.
Volta™s principle Two dissimilar metals brought volume conductivity The reciprocal of VOLUME
into contact (even in air) will generate a difference RESISTIVITY.

of potential whose value is characteristic of the volume control A variable resistor (usually a po-
metals. Also see ELECTROMOTIVE SERIES. tentiometer) or a network of resistors (such as a
volt box A precision, potentiometer-type voltage pad) for adjusting the gain, and, consequently,
divider used in the calibration of meters and the output-signal loudness, of an amplifier.
other instruments. The device is usually provided volume equivalent In wire telephony, speech
with a set of terminal posts for selecting various loudness throughout the system, expressed in
ratios of output voltage to input voltage. terms of the trunk loss in a reference system and
volt-electron See ELECTRONVOLT. adjusted for equal loudness.
voltmeter A usually direct-reading instrument volume expander A circuit or device for automati-
used to measure voltage. Also see ELECTRONIC cally boosting the volume of an audio-frequency
voltmeter-ammeter See VOLT-AMMETER. volume expansion The technique of automatically
voltmeter amplifier A wideband, flat-frequency- increasing the gain, and consequently the
response, low-distortion preamplifier used to output-signal volume, of an audio amplifier. Also
boost the sensitivity of an alternating-current see VOLUME EXPANDER. Compare VOLUME
voltmeter. COMPRESSION.
voltmeter-millivoltmeter A voltmeter that pro- volume indicator A fast-acting alternating-
vides several low ranges, as well as several high current meter used to monitor the volume level in
ones. A familiar example is an alternating- an audio channel in which the signal level is
current voltmeter, which has various full-scale fluctuating. The scale is graduated in VOLUME
ranges from about 1 millivolt to about 1000 volts. UNITS. Also called VU meter.
voltmeter multiplier A resistor connected in se- volume lifetime In a homogeneous semiconduc-
ries with a current meter (usually a milliammeter tor, the interval between minority-carrier genera-
or microammeter) to convert it into a voltmeter. tion and recombination.
voltmeter sensitivity Unit, ohm per volt. For a volume limiter A circuit or device that automati-
voltmeter, the total resistance of the instrument cally holds the volume level of an audio channel
(multiplier resistance plus the resistance of the to a predetermined maximum. Also see VOLUME
meter movement) divided by the full-scale deflec- COMPRESSION and VOLUME COMPRESSOR.
tion of the meter. Thus, a 0-to-10 direct-current volume-limiting amplifier An amplifier that func-
voltmeter with an input resistance of 100 kilohms tions as a volume limiter through the action of
has a sensitivity of 10,000 ohms per volt. volume-limiting subcircuits.

volume magnetostriction • vy

von Hippel breakdown theory The theory that,
Black Red range
assuming no electron-energy distribution, break-
range (high risk of distortion)
down occurs at field intensities for which the re-
combination rate of electrons and holes is lower
than the rate of ionization by collision.
von Neumann architecture In computer systems,
a design scheme in which the bits are transmitted
serially (one by one) along a single line or bus.
VOR Abbreviation of very-high-frequency omni-
range (see VHF OMNIRANGE).
vox Abbreviated form of VOICE-OPERATED CON-
volume indicator
AGE of a field-effect transistor. 2. Symbol for
volume magnetostriction 1. The decrease in the Vp Symbol for VOLTAGE AT PEAK TORQUE.
total volume of certain ferromagnetic substances V particle See VEE PARTICLE.
under the influence of a magnetic field. 2. The in- Vpm Abbreviation of VOLTS PER METER. (Also,
crease in the total volume of certain ferromag- V/m.)
netic substances under the influence of a VR 1. Abbreviation of VIRTUAL REALITY. 2. Abbre-
magnetic field. viation of VOLTAGE REGULATOR.
volume range Unit, decibel (dB). The difference be- VRAM Abbreviation of VIDEO RANDOM-ACCESS
tween the maximum and minimum volume levels MEMORY.
that a device or system can accommodate. Vref Abbreviation of reference voltage.
volume recombination rate Within the volume of vrr Abbreviation of visual radio range.
a semiconductor, the rate at which electrons and V•s Abbreviation of volt-seconds (webers).
holes recombine. V•s/A Abbreviation of volt-seconds per ampere
volume resistance The effective resistance, (henrys).
through a given medium, between two electrodes VSA Abbreviation of VOICE-STRESS ANALYZER.
placed within that medium. VSB Abbreviation of VESTIGIAL SIDEBAND.
volume resistivity The resistance of a specific vol- VSF Abbreviation of VESTIGIAL-SIDEBAND FILTER.
ume of a material (e.g., the resistance between V signal See VEE SIGNAL.
opposite faces of a 1-centimeter cube of the mate- vsr Abbreviation of VERY SHORT RANGE.
volumetric efficiency In an electronic assembly, vt 1. Abbreviation of VACUUM TUBE. 2. Abbrevia-
the ratio of the volume of parts to the total volume tion of variable time.
of the assembly. VT fuse See PROXIMITY FUSE.
volumetric radar A radar providing a three- VTL Abbreviation of VARIABLE-THRESHOLD
dimensional display. LOGIC.
volumetric sensor In security systems, a device vtm Abbreviation of VOLTAGE-TUNABLE MAG-
that detects effects in a specifically defined three- NETRON.
dimensional region, such as an entire room (from VTO Abbreviation of VOLTAGE-TUNABLE OSCIL-
floor to ceiling). LATOR.
volume unit Abbreviation, VU. The unit of mea- VTR Abbreviation of VIDEOTAPE RECORDER or
surement of fluctuating alternating-current VIDEOTAPE RECORDING.
power, such as that of speech or music. Zero VU VTVM Abbreviation of VACUUM-TUBE VOLT-
corresponds to a reference power of 2.51 milli- METER.
watts, or +4 dBm (four decibels above 1 milli- vt voltmeter See VACUUM-TUBE VOLTMETER.
watt). Volume units are measured with a VU Abbreviation of VOLUME UNIT.
VOLUME INDICATOR. vulcanized fiber A tough insulating material de-
volume-unit indicator See VOLUME INDICATOR. rived from cellulose. Dielectric constant, 5 to 8.
volunteer examiner In amateur radio, a person VU meter See VOLUME INDICATOR.
who works with the Federal Communications VVCD Abbreviation of voltage-variable capacitor
Commission (FCC) to administer license exami- diode (see VOLTAGE-VARIABLE CAPACITOR, 1).
nations. Such a person is not actually an em- VVV signal See VEE SIGNAL.
ployee of the FCC, but serves on an independent, VW Abbreviation of volts working (see WORKING
volunteer basis. VOLTAGE).
VOM Abbreviation of VOLT-OHM-MILLIAMMETER. vy Abbreviation for very.
W 1. Symbol for WORK. 2. Abbreviation of WATT.
3. Symbol for TUNGSTEN. 4. Symbol for EN-
ERGY. 5. Abbreviation of west. 6. Abbreviation of
w 1. Abbreviation of WEIGHT. (Also, wt.) 2. Abbre-
viation of week.
WAC Amateur radio abbreviation of Worked All
Continents, an award given to operators who have
engaged in verified two-way communication with
stations on all continents.
wafer 1. Semiconductor die. 2. A thin, flat disk,
ring, or plate around which the contacts of a ro-
tary switch are spaced. 3. A thin square or rect- Wagner
angle of dielectric material used as the dielectric control
member in a fixed capacitor. 4. A plate cut from a
crystal (e.g., a quartz wafer).
wafer fabrication The various processes used in
the manufacture of semiconductor integrated cir-
cuits. Gen
wafer slicing Cutting plates from a mother crystal,
as when piezoelectric plates are cut from a quartz
Wagner ground
(with capacitance bridge)
wafer socket A component socket consisting of a
plastic or ceramic wafer with spring-type contacts
for gripping the pins.
wafer switch A rotary switch whose contacts are waiting time 1. See WARMUP TIME. 2. The delay
arranged around the periphery of a plastic or ce- between the time a data transfer to or from a
ramic wafer. computer memory is called for and the actual
Wagner ground A circuit (often a single poten- transfer of the data. Also called LATENCY.
tiometer) that facilitates cancellation of stray re- walkie-lookie A portable combination camera and
actance in an alternating-current bridge. The transmitter for remote television pickup. At
bridge is balanced alternately with the bridge- sports events and other gatherings, the unit is
balance control and the Wagner control, until strapped to the shoulder of the camera operator.
there is no further shift of null point when chang- walkie-talkie A portable, compact transceiver (or
ing from one to the other. transmitter-receiver).

Copyright © 2001 by The McGraw-Hill Companies, Inc.
Click here for Terms of Use.
wall absorption • water adsorption

wall absorption Diminished radioactive emission warm junction The heated junction in a two-
(especially of beta and gamma rays) because of junction thermocouple circuit. Also called HOT
absorption by the radiating substance. JUNCTION. Compare COLD JUNCTION.
wall box A wall-mounted (usually metal) box en- warmup The process of stabilizing an electronic
closing circuit breakers, fuses, switches, etc. equipment by allowing its temperature to rise to
wall effect In an ionization chamber, the rise in the optimum level.
ionization because of electrons being released by warmup time The time required for an electronic
the walls of the chamber. circuit to become fully operational, or to stabilize,
wall energy In a ferromagnetic substance, the en- after the power has been switched on.
ergy per unit area stored in a domain wall be- warning bell (buzzer) A bell (or buzzer) used as an
tween two regions of opposite magnetization. audible alarm in a WARNING DEVICE.
Wallman amplifier A cascode amplifier (see CAS- warning device A device, such as an electronic sig-
CODE). naler, for alerting a person to an emergency (in-
wall mount A metal bracket for fastening an an- trusion on premises, danger to life and safety,
tenna to a wall. etc.) or to the existence of an intrusion into a se-
wall outlet A plug or socket, usually mounted in a cured area.
protective box or can and recessed in a wall that warning lamp See WARNING LIGHT.
can be accessed from the front. It is commonly warning light A lamp used as a visual alarm in a
used for supplying alternating-current power to warning device.
appliances at 117 volts or 234 volts. It is also warpage Distortion of the normally straight sides
used in telephone and cable-television systems. of a triangular wave.
wall plaque A loudspeaker so thin that, mounted warping In multimedia computer graphics, a
in a frame (sometimes behind grill cloth), it can change in the shape of an object that occurs
be hung on a wall. smoothly over a period of time.
wall plate A (usually rectangular) plate of metal or WAS Amateur radio abbreviation of Worked All
plastic for holding a wall outlet or wall switch. States, an award given to operators who have en-
wall plug A male or female plug usually mounted gaged in verified two-way communication with
in a protective box or can and recessed in a wall. stations in all states of the United States.
Such a device can provide easy access to an an- washer capacitor A very thin donut capacitor.
tenna, telephone line, or load; or it can de- washer resistor A resistor made in the general
liver alternating-current, direct-current, or radio- shape of a washer or ring and having a center
frequency power. hole for a mounting screw or stacking rod.
walls The sides of the groove cut into a record disc. washer thermistor A thermistor made in the gen-
wall socket A male or female socket usually eral shape of a washer and having a center hole
mounted in a protective box or can and recessed for a mounting screw or stacking rod.
in a wall. Such a device can provide easy access washer varistor A varistor made in the general
to an antenna, telephone line, or load; or it can shape of a washer and having a center hole for a
deliver alternating-current, direct-current, or mounting screw or stacking rod.
radio-frequency power. washout process A method of fabricating bipolar
wall speaker See WALL PLAQUE. transistors. The contact metal is deposited in the
wall switch A switch usually mounted in a protec- diffusion hole.
tive box or can and recessed in a wall. waste instruction In a computer program, an in-
wall telephone A wall-mounted telephone set. It struction not meant to be acted upon (e.g., one
generally fits over the jack, so the only cord is be- used to take up space in the listing for some rea-
tween the main unit and the receiver. son). Also called null instruction and dummy in-
wall-through tube See LEAD-IN TUBE. struction.
Walmsley antenna A phased array consisting of watch A work shift, as of electronic personnel (e.g.,
several full-wavelength loops. radio station operators).
wamoscope A radar display tube that performs watchcase receiver An earphone enclosed in a
several microwave-receiver functions (detection, small, round case with a screw-on cap. It is derived
oscillation, amplification, etc.) as well as display- from its resemblance to a large pocket watch.
ing an image. The name is an acronym for wave- water absorption For a solid material, such as a
modulation oscilloscope. dielectric, the ratio of the weight of water ab-
wander See SCINTILLATION, 1. sorbed by the material to the weight of the mate-
warble 1. A periodic rise and fall in the pitch of a water-activated battery A battery that contains
musical tone or combination of tones. 2. To rise all the ingredients of its electrolyte, except water,
and fall in pitch with a definite period. which must be added when the battery is put into
warble-tone generator An audio-frequency oscil- service.
lator whose frequency is varied at a subaudible water adsorption The formation of a thin layer of
rate over a fixed frequency range. water molecules on the surface of normally dry
740 water adsorption • WATS

material, but not by absorption. Also see AD- water glass Sodium silicate, a substance used as a
SORPTION. fireproofing agent and protective coating.
water analogy The useful, but not wholly accu- water ground An earth connection made by drop-
rate, teaching device of comparing an electric ping a weighted wire into a body of water.
current with the flow of water. In such a compar- water jacket In a water-cooled device, the outer
ison, voltage is shown equivalent to water pres- jacket that, along with the outer wall of the cooled
sure, and current to the quantity (e.g., gallons) of component, forms a space through which the
water flowing in unit time. cooling water flows.
water battery A primary battery or cell using water water-level control A servo system that automati-
as the electrolyte. cally maintains or adjusts the level of water in-
water calorimeter A calorimeter used to measure side a tank or other container.
power in terms of the increase in temperature of water-level gauge An electronic system that gives
water heated by the electrical energy. direct water level readings inside a tank or other
water capacitor An emergency capacitor made by container.
setting one glass of water in another larger jar of water-level indicator See WATER-LEVEL GAUGE.
water so that the two bodies of water are sepa- water load 1. A makeshift, power-dissipating re-
rated by the walls of the smaller jar. The bodies of sistive load (see DUMMY LOAD) consisting of a
water, in which an electrolyte has been dissolved, container of tap water or saltwater into which two
form the “plates” of the capacitor, and the wall of wires are immersed. 2. A waveguide termination
the smaller jar serves as the dielectric between containing water heated by the microwave en-
them. ergy. It is usable as a water calorimeter.
water monitor A sensitive electronic instrument
for checking radioactivity in a water supply.
water-pipe ground An earth connection made by
running a wire to the nearest cold-water pipe.
This scheme works only with metal pipes devoid
of insulating joints or splices.
water power Hydroelectric power (i.e., electrical
energy produced by generators driven by water).
water-pressure alarm An electronic circuit that
actuates an alarm when water in pipes or other
channels changes from a predetermined level.
Electrode water-pressure control A servo system for auto-
Jars matically maintaining or adjusting water pres-
sure in pipes or other channels.
water-pressure gauge See WATER-PRESSURE
water capacitor
water-pressure indicator See WATER-PRESSURE
water-cooled tube A power tube, such as a large water-pressure meter An instrument that directly
radio transmitting tube, cooled by the circulation indicates water pressure in a pipe or tank.
of water in the space between the outside of the water-pressure switch A switch that actuates an
tube envelope and a surrounding jacket. alarm when water pressure rises or falls.
water cooling A method of cooling components by water pump In a water-cooled electronic system, the
pumping water through pipes surrounding them. (usually rotary) pump that circulates the water.
water-flow alarm An electronic circuit that actu- water resistor An electrolytic resistor in which the
ates an alarm when the flow of water through electrolyte is tap water or diluted saltwater.
pipes or other channels changes from a predeter- water rheostat A variable water resistor. Usually,
mined rate. the resistance is varied by moving the immersed
water-flow control A servo system for automati- electrodes closer together or farther apart.
cally maintaining or adjusting the flow of water water tester An instrument for checking pH, elec-
through pipes or other channels. trical resistance, and other properties of water.
water-flow gauge See WATER-FLOW METER. water witching Locating underground water by
water-flow indicator See WATER-FLOW METER. electronic methods.
water-flow meter An instrument used to monitor WATS Acronym for Wide Area Telephone Service. A
the flow of water through pipes or other channels, form of long-distance telephone service. Rates are
sometimes showing its direction as well as its charged on a different basis than normal long-
rate. distance service. The system is especially favored
water-flow switch In water-cooled systems (e.g., by businesses because it saves money for sub-
water-cooled tubes), a switch that actuates an scribers making a large number of calls in each
alarm when the water slows or stops. billing period.
watt • wave direction

watt Abbreviation, W. The practical unit of electric reads directly in watts, kilowatts, milliwatts, or
and other power. One watt is dissipated by a re- microwatts. Also see ELECTRONIC WATTMETER.
sistance of 1 ohm through which a current of watt-second Abbreviation, Ws. A small unit of
1 ampere flows. See also KILOWATT, MEGA- electrical energy or work; 1 watt-second = 1 joule
WATT, MICROWATT, and MILLIWATT. = 1/3600 watt-hour. Also see ENERGY and
wattage Electrical power, especially when ex- POWER.
pressed in watts. watt-second constant In an electric-energy meter,
wattage rating 1. The recommended output power the number of watt seconds in one revolution of
of a device. 2. The recommended power dissipa- the indicating disk.
tion of a device. wave 1. A single oscillation of some property of
watt current The component of alternating cur- matter or space, such as density, displacement,
rent that is in phase with voltage. Also called or field strength. It moves outward from a point of
RESISTIVE CURRENT. Compare REACTIVE disturbance and grows weaker as it travels far-
CURRENT. ther. Wave motion is associated with mechani-
watt-decibel conversion The conversion of a cal vibration, sound, radio, heat, light,
power level, such as the power output of an am- X rays, gamma rays, and cosmic rays. See
plifier, in watts to the corresponding power level SOUND and WAVELENGTH. 2. A single cycle of
in decibels, with respect to a reference level. alternating or pulsating current or voltage. Also
Thus, n dB = 10 log10(P/Pref ), where P is the power see AC VOLTAGE, ALTERNATING CURRENT,
of interest (watts), and Pref is the reference level PULSATING DC VOLTAGE, and PULSATING DI-
(e.g., one milliwatt). RECT CURRENT.
watt-hour Abbreviation, WH. The unit of electrical wave absorption The removal of energy from elec-
energy or work; 1 WH = 3600 joules = 10-3 tromagnetic waves as they pass through certain
kWH. Also see ENERGY, KILOWATT-HOURS, media, such as solid bodies, water, and the atmo-
watt-hour capacity The number of watt-hours FLECTION, and WAVE REFRACTION.
that a storage battery can deliver reliably and wave amplitude The peak value of a wave. Also see
safely under specified operating conditions. WAVE CREST and WAVE TROUGH.
watt-hour-demand meter A combination watt- wave analyzer An instrument consisting essen-
hour meter and demand meter. tially of a continuously tunable bandpass filter
watt-hour efficiency For a storage battery, the and an electronic alternating-current voltmeter.
ratio of watt-hours output to watt-hours of As the filter is tuned successively to the funda-
recharge. mental frequency of a complex wave and to its
watt-hour constant In an electric-energy meter, various harmonics, the voltmeter shows the am-
the number of watt-hours in one revolution of the plitude of each of the components. Also see HET-
indicating disk. ERODYNE WAVE ANALYZER.
watt-hour meter An instrument for measuring wave angle The angle, measured with respect to
electrical energy in watt-hours. One well-known the horizon, at which a radio wave is transmitted
type consists essentially of a small motor geared or received.
to a row of four dial indicators. An eddy-current wave antenna See BEVERAGE ANTENNA.
disk keeps the motor speed proportional to the wave attenuation The reduction of wave ampli-
watt-hours consumed by a load, a value which is tude, with respect to distance from the source.
the sum of the readings of the dials. Also called waveband A band of radio frequencies. Also called
TER. waveband switch See BANDSWITCH.
wattless current The component of alternating wave beam Unidirectional radiation from a direc-
current that is out of phase with voltage. Also tive antenna.
called REACTIVE CURRENT. Compare RESIS- wave bounce See WAVE REFLECTION.
TIVE CURRENT. wave clutter Radar interference caused by waves
wattless power The apparent power in a reactive on a body of water, particularly large swells on
circuit, indicated by the product of volts and am- the ocean.
peres. There is no actual power consumption be- wave converter A waveguide part, such as a baf-
cause the power taken by a reactance during a fle-plate or grating, that changes a wave pattern
half-cycle is returned to the generator during the from one type to another.
next half-cycle. Also see AC POWER, APPARENT wave crest The maximum value of a wave enve-
REACTIVE VOLT-AMPERES. wave cycle A complete single alternation of a wave.
wattless volt-amperes See WATTLESS POWER. wave direction The direction in which an electro-
wattless watts See WATTLESS POWER. magnetic wave travels. It is perpendicular to the
wattmeter Abbreviation, WM. An instrument used wave front and depends (whether it is forward or
to measure electrical power. The scale usually backward) upon the direction of the electric and
742 wave direction • waveguide flange

magnetic components. If either is reversed, wave tor (see FUNCTION GENERATOR, 1) is such an
direction reverses; if both are reversed, the direc- instrument, but it usually provides only a choice
tion remains unchanged. of common waveshapes.
wave duct 1. See DUCT, 1. 2. A tubular waveguide wave front For a radio wave, the plane that is par-
in which wave propagation is concentrated. allel to the perpendicular electric and magnetic
wave envelope The outline described by the vari- lines of flux. The wave propagates at right angles
ous amplitude peaks of the cycles in an ampli- to this plane.
tude-modulated wave. The envelope frequency is wave function A point function in a wave equa-
equal to the modulating frequency. tion, specifying wave amplitude.
wave group The resultant of several different-
frequency waves traveling over a common path.
waveguide A transmission line used at ultra-high
and microwave radio frequencies. It is a hollow
metal pipe with a rectangular or circular cross
section. A rectangular waveguide must have
sides measuring at least 0.5 wavelength and
preferably more than 0.7 wavelength. A circular
waveguide should be at least 0.6 wavelength in
diameter, and preferably 0.7 wavelength or more.
The characteristic impedance (Z 0) varies with fre-
quency. In this sense, it differs from coaxial or
parallel-wire lines, whose Z 0 values are indepen-
wave envelope
dent of frequency.
waveguide apparatus See WAVEGUIDE COMPO-
wave equation A second-degree partial differential
waveguide attenuator A device, such as an inter-
equation whose solution describes wave phenom-
posed energy-absorbing plate, for signal attenua-
tion in a waveguide.
wave filter A circuit or device that offers different
waveguide choke flange A waveguide flange that
amounts of attenuation to signals of different fre-
presents no impedance to the signal, and which
need not be metallic for continuity.
waveguide component A device adapted for con-
nection to, or insertion into, a waveguide system.
waveform The shape of a wave described in terms
Such components include waveguide parts and
of its resemblance to some well-known figure or
accessories (e.g., splicing hardware, attenuators,
to its conformity to the curve of the applicable
loads, wavemeters, etc.).
wave equation (e.g., sinusoidal, square, sawtooth,
waveguide connector A fitting for joining wave-
cosine, rectangular, and triangular).
guides for the efficient propagation of a signal.
waveform-amplitude distortion See AMPLITUDE
waveguide coupling See WAVEGUIDE CONNEC-
waveform analyzer See WAVE ANALYZER.
waveguide critical dimension The cross-sectional
waveform converter A circuit or device for chang-
dimension that determines the cutoff frequency
ing a signal of one waveform (such as a sine wave)
for a waveguide.
into one of another waveform (such as a pulse or
waveguide cutoff In a waveguide, the highest or
square wave).
lowest frequency that can be propagated with less
waveform distortion The malfunction evidenced
than a specified amount of attenuation per unit
by a change of the waveshape of a signal passing
through a circuit.
waveguide directional coupler A directional cou-
waveform error In a quantity displayed by an
pler made of two parallel waveguides with a com-
alternating-current test instrument, an error
mon wall. Two slots cut in the wall allow part of
caused by the waveform of the measured signal.
the microwave energy propagated in one direction
Thus, a voltmeter calibrated with a sine-wave
in the main waveguide to be extracted, and en-
voltage is subject to error when a measured sig-
ergy traveling in the opposite direction to be re-
nal is nonsinusoidal. Also called waveform effect.
waveform generator See FUNCTION GENERATOR.
waveguide dummy load A waveguide section that
waveform influence See WAVEFORM ERROR.
dissipates the microwave energy entering it.
waveform monitor In television operations, an os-
waveguide elbow 1. A curved bend in a wave-
cilloscope that continuously displays the video
guide. 2. A waveguide connector with a bend.
waveguide flange A flat, liplike fitting at the end of
waveform synthesizer A variable-frequency signal
the pipe of a waveguide. It fastens waveguide
generator that allows the tailoring of waveshape
sections together or attaches a waveguide
to suit individual applications. A function genera-
waveguide flange • waveguide tee

waveguide post A transverse rod inside a wave-
guide that acts as a parallel susceptance.
waveguide probe A pickup probe (tip or loop, as
required) for sampling the field inside a wave-
Resistor Resistor
guide, or a similar injection probe for introducing
plate rod
energy into a waveguide. Also see WAVEGUIDE
Conducting wires SLOTTED LINE.
waveguide propagation 1. The transmission of
microwave energy through a waveguide by suc-
cessive reflections between the inner walls.
2. Propagation of very-high-frequency (VHF), ultra-
Carbon-coated cloth
Button resistor
high-frequency (UHF), or microwave electromag-
or graphited sand
netic fields through an atmospheric duct (see
DUCT, 1), as if through a waveguide. 3. Propaga-
waveguide dummy load
tion of very-low-frequency (VLF) electromagnetic
fields through a waveguide-like duct between the
ionosphere and the earth™s surface.
waveguide radiator An antenna consisting of an
open-ended waveguide with or without a horn. It
radiates microwave energy into space or to a re-
Greater Greater
than 2» than 2»
waveguide resonator A waveguide section used as
a cavity resonator (see RESONANT CAVITY).
waveguide elbow
waveguide seal A protective cover for the end of a
waveguide. The seal introduces very little mi-
crowave attenuation, while preventing entry of
component, equipped with an identical flange, to
moisture and debris.
the end of a waveguide.
waveguide shim A thin, pliable metal sheet inserted
waveguide frequency meter See WAVEGUIDE
between mating waveguide components for electri-
cal continuity. Also see WAVEGUIDE GASKET.
waveguide gasket A gasket that provides electrical
waveguide shutter An adjustable mechanical bar-
continuity between mating waveguide sections.
rier, such as a rotatable vane, inserted into a
waveguide grating An array of wires mounted in-
waveguide to block or divert microwave energy.
side a waveguide, and that passes signals at
waveguide slotted line A section of waveguide
some frequencies while obstructing others.
having a slot that accommodates a movable
waveguide impedance Where the power P is
probe or coupling element.
known, and voltage E and current I are defined,
waveguide slug tuner A quarter-wave dielectric
with respect to a type of wave and waveguide, the
value is either E 2/P or P/I 2. slug inserted into a waveguide so that its amount
of penetration and position can be adjusted for
waveguide junction A fitting that allows one
tuning purposes.
waveguide section to be joined at an angle to an-
waveguide stub A stub consisting of a waveguide
other section. See, for example, WAVEGUIDE
section joined to a main waveguide at an angle
and provided with a nondissipative termination.
waveguide lens A microwave lens consisting of
waveguide stub tuner An adjustable piston in a
waveguide sections that provide the required
waveguide stub for tuning purposes.
phase shifts.
waveguide switch A switch consisting of a mov-
waveguide load See WAVEGUIDE DUMMY LOAD.
able section of waveguide that can be positioned
waveguide mode The form of propagation indi-
for coupling to one of several other waveguide
cated by the field pattern in a plane transverse
sections; it thus passes the energy it receives to
to the direction in which energy is propa-
any of the other sections.
gated through a waveguide. Common modes are
waveguide system Microwave “plumbing” consist-
ing of waveguides, their fittings and accessories,
and associated components (such as attenuators,
also called TM mode.
loads, wavemeters, etc.).
waveguide mode suppressor A filter that sup-
waveguide taper A connector that is flared to allow
presses undesired propagation modes in a wave-
coupling between two waveguide sections having
different cross-sectional sizes.
waveguide phase shifter A shifter for adjusting
waveguide tee In a waveguide assembly, a tee-
the phase of waveguide output energy, with re-
shaped junction used to connect a section of
spect to input energy.
waveguide in series or parallel with another
waveguide plunger A plunger-like device that re-
flects incident microwave energy in a waveguide.
744 waveguide transformer • wave normal

waveguide transformer A waveguide component wavelength Unit, meter. The displacement in one
that functions as an impedance transformer. complete wave of an alternating or vibrating phe-
waveguide tuner In a waveguide system, an ad- nomenon, generally measured from crest to crest
justable tuner providing impedance transforma- or from trough to trough of successive waves. For
tion. electromagnetic waves in free space, the wave-
length in meters is equal to 3 — 108 divided by the
waveguide twist A length of waveguide whose
cross section is rotated around the longitudinal frequency in Hertz. Also see WAVELENGTH-
axis (e.g., from vertical to horizontal). PERIOD-FREQUENCY RELATIONSHIPS.

than 2»

waveguide twist

waveguide wavelength In a uniform waveguide
operating at a given frequency and in a particular
mode, the distance between similar points for
360° phase shift.
waveguide wavemeter A waveguide component
that acts as an absorption wavemeter or trans-
mission wavemeter for identifying microwave
frequencies. wavelength constant The imaginary-number
component of the propagation constant.
wavelength shifter 1. A frequency shifter whose
performance is indicated in units of wavelength,
Voltage probe Slot for sliding rather than in units of frequency. 2. In certain
probe along guide photosensitive cells and tubes, a photofluores-
Metal cylinder
cent substance that raises the efficiency of the
device by absorbing photons and then releasing
Movable Wave of ones of longer wavelength.
plunger energy
wave mechanics A theory of matter that views
subatomic particles as complex wave patterns,
and attempts to account for all physical pro-
A A cesses in terms of wave phenomena.
wavemeter An instrument for measuring the wave-
length or frequency of radio waves. One form con-
sists of a series-resonant circuit containing an
inductor, variable capacitor, and diode-type me-
ter. The dial of the capacitor is calibrated to read
waveguide wavemeter
in MHz. The inductor picks up energy from the
radio-frequency source of unknown frequency,
waveguide wedge See WEDGE, 1. the capacitor is tuned for peak deflection of the
waveguide window A thin metal opening mounted meter, and the unknown frequency is read from the
transversely inside a waveguide for impedance- dial. This instrument is often called an absorption
matching purposes. The edges of the slit in a ca- wavemeter because it absorbs a certain amount of
pacitive window are perpendicular to the electric power from the signal source under test. See also
field; in an inductive window, they are parallel to CAVITY WAVEMETER, COAXIAL WAVEMETER,
the electric field. LECHER WIRES, and SLOTTED LINE.
waveguide wye In a waveguide assembly, a wye- wave motion Undulating motion (e.g., up and
shaped junction for joining three waveguide sec- down, and side to side). An electromagnetic wave
tions. has undulating electric and magnetic compo-
wave heating Heating a material by energy ab- nents that are both in phase and perpendicular
sorbed from traveling electromagnetic waves. to each other and to the direction of propagation
wave interference Interaction between two or of the wave.
more waves, resulting in reinforcements and can- wave normal 1. The direction of propagation of an
cellations of energy. electromagnetic wave. 2. A unit vector directed at
wave normal • way station

a right angle to both the electric and magnetic
lines of flux in an electromagnetic wave.
wave number The reciprocal of wavelength. This
number denotes the number of waves per unit
wave packet A short pulse composed of waves.
wave packets Radiant energy resulting from a
number of wave trains of different wavelength.
wave path The line along which a WAVE TRAIN is Output
wave polarization The direction (horizontal or ver-
tical) of wave undulations (i.e., the plane of the
undulations, with respect to the direction of
propagation). In general, a vertical antenna
radiates a vertically polarized wave, and a
horizontal antenna radiates a horizontally wavetrap
polarized wave.
wave propagation The movement of waves
through space or through some medium. Electro- signal at the resonant frequency from a signal
magnetic waves travel through space at the speed mixture.
of light (approximately 3 — 108 meters, or 186,000 wave trough The minimum value of a wave enve-
miles, per second) and, like light, can be reflected lope. Compare WAVE CREST.
and refracted. wave velocity The distance per unit time traversed
wave reflection The reflection of electromagnetic by a wave passing through a given medium.
waves by an obstruction, such as a solid body or wave winding See DRUM WINDING.
a layer of the ionosphere. Compare WAVE AB- wa-wa pedal A foot-operated device used with an
SORPTION, WAVE POLARIZATION, and WAVE electronic musical instrument to produce a “wah-
REFRACTION. wah” sound fluctuation.
wave refraction Bending of the line of propagation wax 1. Any of a series of organic materials having
of electromagnetic waves as they pass through important uses as dielectrics, impregnants, seal-
various media, such as the troposphere or the ers, and lubricants in electronics. They are usu-
ionosphere. Compare WAVE ABSORPTION, ally solid or semisolid, waterproof, and easily
WAVE POLARIZATION, and WAVE REFLECTION. melted. 2. In certain phonograph record discs, a
waveshape The overall contour of a wave”espe- blend of wax (see 1, above) and metallic soaps.
cially as revealed by a curve plotted for the par- Also see WAX MASTER, 2.
ticular wave equation. Also see WAVEFORM. wax cake See WAX MASTER, 1, 2.
waveshaping circuit A circuit that receives an in- wax capacitor A fixed capacitor that has been
put signal having a certain waveshape, and deliv- dipped in or impregnated with a wax, such as
ers an output signal having a different waveshape. halowax.
For example, a squaring circuit converts a sine wax-dipped capacitor A fixed capacitor that has
wave into a square wave at the same frequency. been dipped in a wax for sealing against moisture.
wave surface See WAVE FRONT. waxed paper See WAX PAPER.
wave tail In a decaying pulse or signal envelope, the wax-filled capacitor A fixed capacitor impregnated
interval between the beginning of the decay and with a wax for enhancing the properties of its di-
the point at which the amplitude reaches zero. electric (usually paper) and sealing the capacitor
wave telegraphy See RADIOTELEGRAPHY. unit.
wave telephony See RADIOTELEPHONY. wax master 1. In disc-recording operations, the
wave theory of matter A physical theory that the original recording made on a wax-surface disc.
charge of an electron is distributed in space, 2. To make an original recording on a wax-
rather than being focused at a point. Also see surface disc.
wave tilt A slight forward tilt of the electric flux wax paper Wax-saturated paper used as a dielec-
lines in a radio wave radiated at the surface of the tric film in fixed capacitors and as an insulator.
earth by a vertical antenna. way-operated circuit A single or duplex circuit
wave train A series of identical electromagnetic shared by three or more party stations.
wave cycles propagated at equal intervals; an way point An important point selected on a ra-
electromagnetic energy burst lasting at least sev- dionavigational course line.
eral cycles. way station A station consisting of a teletypewriter
wavetrap A resonant circuit consisting of an in- connected at an intermediate point in a line (i.e.,
ductor and capacitor, either or both of which can between, and in series with, other teletypewriter
be adjustable for tuning, used to remove (trap) a stations).
746 WAZ • weighted noise level

WAZ Amateur radio abbreviation of Worked All weathering Deterioration of electronic equipment
Zones, an award given to operators who have car- as a result of exposure to outdoor heat, cold,
ried on verified two-way communication with sta- moisture, wind, and similar conditions.
tions in all communications zones of the world. weather-protected machine A machine (usually a
WB Abbreviation of weather bureau. generator or motor) whose vent holes are de-
WB Abbreviation of base-region width (in a transis- signed to prevent entry of dust, water, and debris.
tor). weather protection The coating, sealing, or treat-
Wb Symbol for WEBER. ing of electronic equipment for protection against
Wb/m2 Abbreviation of Webers per square meter corrosion, humidity, and temperature changes in
(see TESLA). outdoor use.
WC Abbreviation of collector-region width (in a tran- weather satellite A satellite designed to photo-
sistor). graph weather systems in infrared and/or visible
WCEMA Abbreviation of West Coast Electronic light, and relay the pictures to earth via facsimile
Manufacturers™ Association. or television.
W/cm2 Abbreviation of watts per square centime- weather sonde See RADIOSONDE.
ter. weather transmission The radio transmission of
WE Abbreviation of write enable. meteorological reports. Sometimes the transmis-
WE Abbreviation of emitter-region width (in a tran- sions are combined with guidance transmissions,

sistor). from which they can be separated by means of a
weak battery 1. A battery that has been depleted filter in the receiver.

to the point that its output (no-load or full-load) is weber Abbreviation, Wb. The SI unit of magnetic
too low to be useful. 2. A battery specially de- flux and of the magnetic flux quantum; 1 Wb =
108 maxwells = 1.257 — 10“7 unit pole.
signed for low-voltage output.
weak color Lack of color vividness or poor contrast Weber-Fechner law The law expressing the rela-
between colors in a color-television picture. The tionship between a stimulus and the physiologi-
condition is often caused by some malfunction in cal reaction it produces: The sensation is
the chroma demodulator(s). proportional to the logarithm of the stimulus.
weber per square meter Symbol, Wb/m2. See
weak contrast In a television picture, poor differ-
entiation of adjacent tonal areas. TESLA.

weak coupling See LOOSE COUPLING. weber turn A unit of magnetic flux linkage equal to
108 maxwell turns.
weak current An extremely small electric current.
The term is relative; generally, it refers to cur- wedge 1. In a waveguide, a termination consisting
rents of a few microamperes or less. of a tapered block or plate of carbon (or other dis-
weak magnet 1. A magnet whose power has dete- sipative material). 2. In a television test pattern,
riorated considerably below a prescribed level. convergent, equally spaced lines for checking res-
2. A body that normally is only slightly magnetic. olution.
weak signal A signal whose amplitude is very low wedge bonding In integrated-circuit fabrication, a
compared with that of signals considered satis- method of bonding in which a thermocompres-
factory in a given application. Although the term sion bond (see COLD-COMPRESSION WELDING)
is relative, it usually implies a signal that is non- is obtained through pressure from a wedge-
competitive with other signals in a given environ- shaped tool.
ment. Wehnelt cathode An oxide-coated cathode in an
weak-signal detector A detector in which, at low electron tube.
input-signal amplitudes (weak-signal levels), Wehnelt cylinder In a cathode-ray tube, the
the direct-current output is proportional to the cathode-enclosing cylinder that concentrates the
square of the root-mean-square (rms) value of the electrons emitted by the cathode.
input-signal voltage. weight 1. The amount of gravitational pull on a
wearout The complete deterioration of a compo- body or particle. 2. Extra significance given to a
nent or system (i.e., beyond restoration to useful term or value. See, for example, WEIGHTED
service). TERM. 3. The dot-to-space ratio in a Morse-code
wearout failure Failure because of wearout, which signal.
weight-density Symbol, d. Unit, kg/m3. The
can be predicted on the basis of known lifetime
and the deterioration characteristics of compo- weight per unit volume of a liquid, such as an
nents and equipment. electrolyte or insulating oil; also called density.
wearout point The instant of wearout, in terms of weighted distortion factor In the measurement of
power output, watt-hour capacity, or some other harmonic distortion, a factor whose use allows
specification. the harmonics in the complex waveform to be
weather antenna An antenna dimensioned for weighted in proportion to their relationship.
reception exclusively in the 162.4- to 162.55- weighted noise level Unit, dBm. The noise level
MHz weather band. See WEATHER TRANSMIS- weighted with respect to the 70-dB equal-
SION. loudness contour of hearing.

weighting • wet electrolytic capacitor

Mark trons, ignitrons, or silicon-controlled rectifiers in
the welding circuit. The control system can also
regulate the welding current.
Time welding current The high electric current passed
through a workpiece to produce the heat required
for welding.
welding cycle The required sequence of steps (and
Time the time required) in making a weld electroni-
welding time See WELD TIME.
welding transformer For electronic welding, a
special very-high-current step-down transformer.
weld junction See WELD.
weight, 3
weld polarity The polarity of welding current.
Some materials require a certain direction of cur-
rent flow for a good weld.
weighting 1. Adjustment of a parameter to com-
weld time The interval during which welding cur-
pensate for some imbalance in a system. 2. Ad-
rent flows through the bodies to be bonded to-
justment of the dot-to-space ratio in a Morse code
signal. 3. Adjustment of the mark-to-space ratio
well counter A radiation-counter setup in which a
in a digital communications signal.
radioactive sample and detector are enclosed to-
weighting filter A filter used in a communications
gether in a thick-walled (usually lead) cylinder to
network to represent the characteristics of the
minimize background count.
transmission passband.
well-structured language An advanced form of
weighting network A network that weighs differ-
high-level computer programming language. It is
ently (in a prescribed ratio) the frequency compo-
used in graphical and control applications.
nents appearing in an output signal by offering
Wenner element An adjustable, dual-slidewire
unequal attenuation to those frequencies.
balancing resistor used in constant-current, lab-
weightlessness switch See ZERO-GRAVITY
oratory potentiometers to eliminate the necessity
for sliding contacts in the measuring circuit.
Weir circuit In frequency-modulated signal trans-
Wenner winding A low-capacitance, low-induc-
mission, a circuit used to stabilize the carrier
tance winding for high-frequency wirewound
wave. It compares the average carrier frequency
resistors in which the direction of the wire is
with the frequency of a standard crystal oscilla-
reversed by looping alternate turns along the
tor, obtaining a direct-current compensating volt-
age (proportional to frequency deviation) that is
Wertheim effect The tendency for a potential dif-
applied to the frequency modulator. Also called
ference to develop between opposite ends of a
Weir stabilization circuit.
length of wire, when the wire is placed parallel to
Weiss constant In paramagnetism, a constant
magnetic lines of flux and rotated.
also known as paramagnetic Curie temperature. It
Western Union joint A strong splice of two wires
can be positive or negative, depending on the par-
made by tightly twisting a short portion of the tip
ticular paramagnetic material. It is important in
of each wire along the body of the other. For in-
defining the behavior of certain paramagnetic
creased ruggedness, the joint is often soldered.
Also called Western Union splice.
weld A strong bond of materials (usually metals)
Weston cell See STANDARD CELL.
obtained by applying heat to areas to be joined
Westrex system A system of sound recording in
while they are held or pressed together. No for-
which signals from two separate microphone
eign metal is used, as is the case in brazing and
channels are recorded on opposite walls of a
soldering. The required heat is sometimes ob-
groove on a disc.
tained by passing a high electric current through
wet battery A battery of cells having a liquid elec-
the materials.
welder 1. An electrical device, often electronically
wet Liquid, especially pertaining to the electrolyte
controlled, for welding materials. 2. A person who
material in an electrochemical cell.
operates a device, as defined in 1.
wet cell A battery cell having a liquid electrolyte.
weldgate pulse In a welding device, the pulse that
Compare DRY CELL.
affects the arc current; therefore, it also affects
wet-charged stand The length of time that a fully
the intensity of the heat produced by the device.
charged, wet storage cell can stand idle before its
welding control An electronic system for control-
capacity drops by a specified amount.
ling the interval during which current is passed
wet electrolytic capacitor An electrolytic capaci-
through a workpiece in spot welding or seam
tor in which the electrolyte is a liquid. The leak-
welding. In this system, an electronic timer cir-
age current in this type is higher than in the dry
cuit determines the conduction time of thyra-
748 wet electrolytic capacitor • whistle filter

electrolytic, but it is self-healing after momentary l
voltage breakdown. Compare DRY ELEC-
wet grab The adherence of a pressure-sensitive
tape or sheet to a surface when very little pres- b
sure is used.
wet shelf life The specified shelf life of a dis-
charged, wet storage cell. Compare DRY SHELF
0.8 a2n2
6a 9l 10b
wetted-contact relay See MERCURY-WETTED
wetting Applying a mercury coating to a contact
wetting agent A substance (such as an alcohol or Wheeler™s formula
ester) that promotes the spreading and adhesion (dimensions illustrated)
of a liquid or its absorption by a porous material.
WG Abbreviation of WIRE GAUGE.
WH Abbreviation of WATT-HOUR. wheel pattern A frequency test pattern produced
wh Abbreviation of WHITE. on an oscilloscope screen by z-axis modulation of
Wheatstone bridge A four-arm balancing circuit a circular trace. A sinusoidal axis signal produces
(see BRIDGE), having resistors in each arm and a gear-wheel pattern, and a square-wave or pulse
used to measure an unknown resistance in terms z-axis signal produces a spot-wheel pattern.
of a standard resistance. The bridge supply is usu- wheel printer A printout device for computers and
ally direct current, but alternating current can be calculators. It consists essentially of a rotating
used if all four resistances are nonreactive. metal wheel around whose rim letters and num-
bers stand in relief. When the desired character
comes into position, a hammer strikes it through
the recording paper and carbon paper, printing
the character on the recording paper. Also called
R1 R2 daisy-wheel printer.
wheel static Static electricity (and the resulting
radio interference) generated by friction between
automobile tires and the road.
whiffletree switch In computer operations, a mul-
tiposition electronic switching circuit, so called
from its circuit configuration, which resembles
the contrivance used between a wagon and the
R3 Rx
horse team pulling it.
whip antenna A small-diameter, vertical rod (often
telescoping) used as an antenna”especially in
mobile communications, portable radio and tele-
vision receivers, field-strength meters, etc.
whirl One of the circular, magnetic lines of flux
Rx = R3(R2/R1)
around a straight wire carrying current.
whisker 1. The pointer-wire electrode of a point-
Wheatstone bridge
contact diode, point-contact transistor, or crystal
detector. 2. A slender filament of metal or ce-
ramic, having high purity and high tensile
wheel-drive locomotion The use of wheels for


. 40
( 42)