18WuD2x

156 cryotron • crystal loudspeaker
superconductive at a temperature of approximately
4.4 degrees K.
cryotronics Low-temperature electronics, concerned
with such phenomena as superconductivity.
The term is an acronym from cryogenics and
electronics. Also see CRYOGENICS.
cryptanalysis The breaking of ciphers.
crypto- A prefix added to words, that implies encoding
for the purpose of changing or hiding the
meaning of a message or signal.
cryptography The creating and writing of ciphers.
cryptology The art and science of creating, writing,
unscrambling, and breaking ciphers.
crystal 1. A material distinguished by the arrangement
of its atoms into a redundant pattern called
a lattice that presents, in fragments of various
sizes, a characteristic polyhedral shape. Common
shapes include cubes, parallelepipeds, and
hexagonal prisms. 2. A fragment of material as
defined in (1). 3. A plate or bar cut from a piece of
piezoelectric material.
crystal amplifier 1. A semiconductor diode circuit
using carrier storage. Transistor action and, accordingly,
pulse amplification is obtained by alternately
making one electrode of the diode an
emitter or collector. 2. Archaic term for TRANSIS-
TOR.
crystal audio receiver An audio radar receiver,
consisting of a crystal detector and audio-amplifier
stages.
crystal axes The imaginary lines traversing a piezoelectric
crystal, along which (or perpendicular
to which) plates are cut for oscillators, resonators,
or transducers.
crystal calibrator A crystal oscillator used to
generate harmonic checkpoints for frequency
calibration. Common fundamental calibrator
frequencies are 100 kHz and 1 MHz.
crystal capacitor See VARACTOR.
crystal control The control of the operating frequency
of a circuit by means of a piezoelectric
crystal.
crystal-controlled receiver A superheterodyne
radio receiver whose local oscillator is crystal
controlled.
crystal-controlled transmitter A radio transmitter
whose master oscillator is crystal controlled.
crystal counter A device for counting the frequency
of subatomic particles, based on their
ability to change the conductivity of a crystal. The
particles can be photons, electrons, protons, neutrons,
or the nuclei of atoms.
crystal current Current flowing through a crystal;
specifically, the radio-frequency (RF) current
flowing through a quartz plate in a crystalcontrolled
oscillator.
crystal cuts The classification of piezoelectric
plates according to the angle at which they were
cut from a quartz crystal. Common cut designations
are AT, BT, CT, DT, X, Y, and Z. Various
cuts afford such complementary factors as fre-
X cut
35°
Z axis
(center of crystal)
quency, temperature, and thickness. Also see
CRYSTAL AXES.
crystal detector A rudimentary form of semiconductor
diode consisting of a mounted lump of
mineral (the crystal) in contact with a springy
wire (“cat’s whisker”). The point of the wire is
moved to various points of contact on the crystal
surface until the most-sensitive rectifying spot is
found.
crystal diffraction The tendency of electromagnetic
waves to be scattered when passing through
a crystal material.
crystal diode Archaic term for SEMICONDUCTOR
DIODE. Also see GALLIUM-ARSENIDE DIODE;
GERMANIUM DIODE; JUNCTION DIODE; LASER
DIODE; POINT-CONTACT DIODE; SELENIUM
DIODE; SIGNAL DIODE; SILICON DIODE.
crystal earphone An earphone in which the transducer
is a piezoelectric crystal. Electrical impulses
applied to the crystal vary its shape and
cause a vibration that is transmitted to a diaphragm;
this in turn produces corresponding
sound waves.
crystal filter See CRYSTAL RESONATOR.
crystal headphone See CRYSTAL EARPHONE.
crystal holder A fixture specially designed to hold
a piezoelectric crystal; it ensures minimum distortion
of crystal dimensions and minimum residual
capacitance, inductance, and resistance.
crystal imperfection A flaw in the lattice structure
of a crystal.
crystal lattice The orderly, redundant pattern of
atoms and molecules within a crystalline material;
it is a characteristic of a given material.
crystal-lattice filter A crystal resonator in which
piezoelectric crystals are used to give a desired
shape to the filter response curve.
crystalline material A material exhibiting the
characteristic properties of a crystal (see CRYS-
TAL, 1).
crystallogram An X-ray photograph or other
record of crystal structure.
crystallography The science dealing with crystals
and their properties (see CRYSTAL, 1).
crystal loudspeaker A loudspeaker whose transducer
is a piezoelectric crystal. Electrical impulses
applied to the crystal vary its shape and
X
Y
crystal cuts
Y cut
AT cut