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20 align • alloy diode
align 1. To adjust (i.e., to preset) the circuits of an
electronic system, such as a receiver, transmitter,
or test instrument, for predetermined response.
2. To arrange elements in a certain
precise orientation and spacing, relative to each
other, as in a Yagi antenna. 3. To orient antennas
so that they are in line of sight, with respect to
each other.
alignment The process of ensuring that equipment,
components, or systems are adjusted, both
physically and electronically, for the most efficient
possible performance.
alignment chart A line chart for the simple solution
of electronic problems. It is so called because
its use involves aligning numerical values on various
scales, the lines intersecting at the solution
on another scale. Also called nomograph.
alignment pin A pin or protruding key, usually in
the base of a removable or plug-in component, to
ensure that the latter will be inserted correctly
into a circuit. Often, the pin mates with a keyway,
notch, or slot.
alignment tool A specialized screwdriver or
wrench (usually nonmagnetic) used to adjust
padder or trimmer capacitors or inductor cores.
alive See LIVE.
alkali See BASE, 2.
alkali metals Metals whose hydroxides are bases
(alkalis). The group includes cesium, francium,
lithium, potassium, rubidium, and sodium.
alkaline battery 1. A battery composed of alkaline
cells and characterized by a relatively flat discharge
curve under load.
alkaline cell A common non-rechargeable electrochemical
cell that employs granular zinc for
the negative electrode, potassium hydroxide as
the electrolyte, and a device called a polarizer as
the positive electrode. Produces approximately
1.5 volts under no-load conditions. The geometry
of construction is similar to that of the zinc–
carbon cell, but it can deliver current effectively
at lower temperatures. Cells of this type have
shelf lives longer than zinc–carbon cells; they also
have greater energy-storage capacity per unit
volume, but they are more expensive than zinc–
carbon cells. They are used in calculators, transistor
radios, and cassette tape and compact-disc
players. Compare ZINC–CARBON CELL.
alkaline-earth metals The elemental metals barium,
calcium, strontium, and sometimes beryllium,
magnesium, and radium, some of which are
used in vacuum tubes.
alkaline earths Substances that are oxides of the
alkaline-earth metals. Some of these materials
are used in vacuum tubes.
all-diffused A type of INTEGRATED CIRCUIT in
which both active and passive elements have
been fabricated by diffusion and related processes.
Allen screw A screw fitted with a six-sided (hexagonal)
hole.
Allen wrench A tool used to tighten or loosen an
Allen screw. It is a hexagonal rod and is available
in various sizes.
alligator clip A spring-loaded clip with jagged
teeth, designed to be used for temporary electrical
connections.
allocate 1. To assign (especially through legislation)
operating frequencies or other facilities or
conditions needed for scientific or technical activity;
see, for example, ALLOCATION OF FRE-
QUENCIES. 2. In computer practice, to assign
locations in the memory or registers for routines
and subroutines.
allocated channel A frequency channel assigned
to an individual or group.
allocated-use circuit 1. A circuit in which one or
more channels have been authorized for the exclusive
use of one or more services. 2. A communications
link assigned to users needing it.
allocation of frequencies See RADIO SPECTRUM.
allocator A telephone system distributor associated
with the finder control group relay assembly.
It reserves an inactive line-finder for another call.
allophone A variation in the sound of a phoneme,
depending on what comes before and/or after the
phoneme in the course of speech. Important in
speech recognition and synthesis. There are 128
different phoneme variations in the English language.
See PHONEME.
alloter relay A telephone system line-finder relay
that reserves an inactive line-finder for the next
incoming call from the line.
allotropic Pertaining to a substance existing in
two forms.
alloy A metal that is a mixture of several other metals
(e.g., brass from copper and zinc), or of a
metal and a nonmetal.
alloy deposition In semiconductor manufacture,
depositing an alloy on a substrate.
alloy-diffused transistor A transistor in which the
base is diffused and the emitter is alloyed. The
collector is provided by the semiconductor substrate
into which alloying and diffusion are
affected. Compare ALLOY TRANSISTOR and
DIFFUSE TRANSISTOR.
alloy diode A junction-type semiconductor diode
in which a suitable substance (such as p-type) is
alloyed into a chip of the opposite type (such as