the Aviation Dictionary

differentiating circuit . dinole antenna
If the generator voltage falls below the battery voltage, dimension -A measurement of length, width, thickness,
the battery will be reconnected.
size, or degree listed within a drawing.
differentiating circuit - A circuit that produces an
output voltage proportional to the rate of change in
input voltage.
diffuser - 1. A duct used on a centrihgal flow turbine
engine - to reduce the velocity of the air and increase its
pressure. 2. The divergent section of a gas turbine
engine used to convert velocity energy of compressor
discharge air into pressure energy.
diffuser vane - A turning or cascading vane in a
centrifugal flow engine diffuser used to change air
from a radial direction as it leaves the impeller to an
axial direction as it moves into the combustor.
dimension line - A light solid line broken at its
midpoint for insertion of measurement indications.
Dimension lines typically have outward pointing
arrowheads at each i d to show origin and termination
of a measurement.
dimensional inspection - The physical measurement of
a part against a recognized standard to determine the
amount of wear or deformation of the part.
dimmer - A device that controls illumination. Can be
either a simple rheostat or a variable pulse control.
dimming relay - A relay that allows a light or lights in a
circuit to be dimmed.
diffusion - 1. A process where particles of liquids,
dimming rheostat - A rheostat used to control the
gases, or solids move ftom a region of higher
degree of brilliance of a lighting circuit.
concentration to one of lower concentration. 2. The
scattering of light by a rough surface or by dimpling - A process used
transmission through a translucent material. to indent the hole into l - p \
which a flush rivet is to be
diffusion welding - A method of fusing materials to
installed. Some metals
each other that relies on the two materials being
such as the harder aluminum alloys cannot be dimpled
pressed together under high pressure and the joint
while the metal is cold because it is likely to crack.
heated to less than melting temperature. The two pieces
This type of metal must be hot dimpled. Hot dimpling
fuse together without the strength degradation found
equipment consists of a pair of electrically heated dies
with normal welding.
with a pilot that is inserted into the rivet hole. The pilot
digital readouts -The presentation of information by an is passed through the hole and the heated dies are
instrument in a digital form such as light emitting pressed together. The dies heat the metal enough to
diodes or drums, rather than by the movement of a soften it and force it into the shape of the die.
pointer over a numbered dial.
diode - A device that allows a flow of electrons in one
digital voltmeter - A voltage measuring device that direction but not the opposite. Also referred to as an
reads out in digital form rather than an analog dial.
electron check valve.
digitize - To change an analog reading to digital format
(binary) that can be used by a computer.
dihedral - The positive acute angle between the lateral
axis of an airplane and a line through the center of a
wing or horizontal stabilizer.
dikes - A common expression for diagonal cutting
pliers.
dip - A vertical attraction between a compass needle
and the magnetic poles. The closer the aircraft is to the
pole, the more severe the effect. In the Northern
Hemisphere a weight is placed on the south-facing end
of the compass needle; in the Southern Hemisphere a
weight is placed on the north-facing end of the
compass needle to somewhat compensate for this
effect.
diluent - A material used to change the concentration of DIP (Dual Inline Packaging) - A standard
some other substance without changing the configuration used for chips, DIP switches, etc., used
characteristics of the base material. Common diluents on computer circuit boards.
include water- used to dilute salt water solutions and
dip coating - A process of coating various products
water-based paints and paint thinners used to dilute oilwith
a soft, rubber-like, plastic coating applied by
based paints.
dipping the product into a container of plastic coating.
diluter-demand oxygen system - An oxygen system often used tb insulate the handles of hid tools.
that delivers oxygen mixed or diluted with air in order
dip soldering - A process of lowering a printed circuit
to maintain a constant oxygen partial pressure as the
board onto the top of a container of molten solder in
altitude changes.
order to solder the leads of components that extend
dilution air - The portion of combustion secondary air through the board.
used to control the gas temperature immediately prior
to its entry into the turbine nozzle area.
dipole antenna - A center-fed, half-wave antenna.
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