18WuD2x

Y 1. Symbol for ADMITTANCE. 2. Symbol for
YTTRIUM. 3. Symbol for YOUNG’S MODULUS.
y 1. Abbreviation of YEAR. (Also, yr.) 2. Abbreviation
of YARD. (Also, yd.) 3. Symbol for the vertical
axis of a graph or screen in the rectangular
(Cartesian) coordinate system.
Y adapter See WYE ADAPTER.
YAG Abbreviation of yttrium-aluminum-garnet, the
stimulated substance in some lasers.
Yagi antenna Also called Yagi-Uda array or beam.
An antenna consisting of two or more parallel,
straight elements, including at least one parasitic
element and at least one driven element. The elements
all lie in the same plane. Each driven element
is connected to the feed line, half-wave
resonant, and center-fed. A two-element array
can be formed by adding a director or a reflector
alongside a single driven element. An array with
one director and one reflector, along with the
driven element, increases the gain and directivity
compared with a two-element system. The gain
and directivity increase further as elements are
added. This is usually done by placing additional
directors in front of a three-element array. Compare
QUAD ANTENNA.
y amplifier The vertical amplifier of an oscilloscope
or recorder. Compare X AMPLIFIER and Z AMPLI-
FIER.
Yankee Phonetic alphabet communications code
word for the letter Y.
yard Abbreviation, yd. A unit of linear measure in
Parasitic
reflector
Radiator
Feeder
Parasitic
directors
}
Mast
yagi antenna
the English system. 1 yd = 3 ft = 36 inches =
0.9144 meter.
yaw Side-to-side movement in a vehicle or robotic
end effector. Essentially horizontal displacement
about the vertical axis.
yaw amplifier In an aircraft servo system, the unit
that amplifies the yaw signal (the signal proportional
to the deviation of the aircraft from the line
of flight).
yaw meter An instrument for measuring the angle
of yaw of an aircraft.
y-axis 1. The vertical axis of a chart, graph, or
screen in the rectangular coordinate system.
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