Page 35 - The Illustrated Dictionary of Electronics

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20 align • alloy diode

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