18WuD2x

722 velocity resonance • versatile automatic test equipment
velocity resonance A state of resonance in which
a 90-degree phase difference is between the fundamental
frequency of oscillation of a system and
the fundamental frequency of the applied signal.
velocity sorting Selecting and separating electrons,
according to their velocity.
velocity spectrograph A device that uses electric
or magnetic deflection to separate charged particles
into various streams, according to their velocity.
velocity variation See VELOCITY MODULATION.
velocity-variation amplifier See VELOCITY-
MODULATED AMPLIFIER.
velocity-variation oscillator See VELOCITY-
MODULATED OSCILLATOR.
velometer An instrument used to measure the velocity
of air (e.g., to determine wind speed).
venetian-blind effect A television-display malfunction
in which the picture seems to appear
through horizontal slits.
Venn diagram A method of illustrating the relationship
among various subsets within a specified
universal set. The subsets are shown as
geometric figures, usually circles.
vented-baffle loudspeaker See ACOUSTICAL
PHASE INVERTER and BASS-REFLEX LOUD-
SPEAKER.
vent mount A metal bracket for fastening an antenna
mast to a (plumbing) vent pipe on a roof.
ventricular fibrillation See FIBRILLATION.
verification 1. The process of ensuring that two
sets of data are identical. 2. The process of validating
(see VALIDATE).
vernier 1. An auxiliary scale along which a regular,
linear scale (such as that of a tuning dial)
slides. The vernier scale is graduated so that
when the main scale is set to an unmarked point
between two of its graduations, and the “0” point
on the vernier scale is used as the index, “1” on
the vernier scale will exactly coincide with “1” on
the main scale. The corresponding number on the
vernier scale indicates the exact number of subdivisions
between two points on the main scale.
Vernier arrangements are provided with the dials
of some precision analog instruments. 2. See
VERNIER CAPACITOR. 3. See VERNIER DIAL.
4. See VERNIER RESISTOR.
w1
Universal set
Main
reading
line
Aux. scale
x
w2
y
1 2 3
4 5
6 7
8 9
x1
x2
x3
x5
x4
z1
y3
y1
y2
z2
y4
y5
y6
70
Reading is
somewhere
between
75 and 76
vernier, 1
80
Aux. scale lines up at 3,
indicating 75.3
z
Venn diagram
vent 1. An opening in an equipment enclosure for
the entry of cool air or the escape of warm air.
2. In an electrolytic capacitor, a lightly covered
blowout hole for the relief of gas pressure in the
event of severe overload. 3. A small opening for
relieving gas pressure in an automobile battery.
4. In a loudspeaker enclosure, such as the bassreflex
type, an auxiliary opening that extends the
low-frequency range of the speaker.
vented baffle A loudspeaker enclosure having the
proper auxiliary opening(s) for coupling the
speaker to the surrounding air.
w3
vernier capacitor A low-capacitance variable capacitor
connected in parallel with a higher-capacitance
fixed or variable capacitor for precise
adjustment of the total capacitance.
vernier dial 1. A slow moving dial for fine tuning
an adjustable device. The required reduction ratio
is obtained with gears, friction wheels, or a
belt-and-pulley combination. 2. A dial provided
with an accessory vernier scale.
vernier resistor A low-resistance variable resistor
connected in series with a higher-resistance fixed
or variable resistor to precisely adjust the total resistance.
vernier rheostat See VERNIER RESISTOR.
vers Abbreviation of VERSED SINE.
versatile automatic test equipment Abbreviation,
VATE. For troubleshooting the electronic
systems of missiles, a computer-controlled tester
that isolates faults through logical operations.