SEVENTH EDITION
`
`:
`
`DIUIONARY
`ELEGRONKS
`
`WI'IES
`
`RUDOLH. GRAF
`
`F
`
`JE
`
`AMD EX1036
`U.S. Patent No. 6,239,614
`
`0001
`
`

`

`MODERN
`DICTIONARY
`of
`
`ELECTRONICS
`
`SEVENTH EDITION
`
`REVISED AND UPDATED
`
`Rudolf F. Graf
`
`Boston Oxford Auckland Johannesburg Melbourne New Delhi
`
`Newnes
`
`
`
`0002
`
`0002
`
`

`

`Newnes is an imprint of Butterworth—Heinemann.
`
`Copyright © 1999 by Rudolf F. Gral'
`
`-& A member of the Reed Elsevier Group.
`
`All rights reserved.
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`2mm
`
`Library of Congress Cataloging-in-Publicatiou Data
`
`Graf. Rudolf F.
`Modern dictionary of electronics f Rudolf F. Graf. -—?th ed“
`revised and updated.
`13.
`cm.
`ISBN 0-7506-9866-7 (alk. paper)
`1. Electronics —-Dictionaries. I. Title
`TK7804.G67
`1999
`621,331'03—dc21
`
`99-17389
`CH3
`
`British Library Cataloguing-in-Publication Data
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`0003
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`0003
`
`

`

`A positive (A+ or A plus) - AOL
`
`first launched into highly elliptical orbits with apogw; of
`22.23? miles. When the communication gatzllttc infill?
`thca
`ro riatc n
`ce.arockct motor at
`re
`toPaC‘E ‘3
`satcllili: iiito its filament circular orbit of 22.23? miles.
`Also see perigee.
`_
`_
`_
`A positive (A+ or A plusi——t. Posntve tenntrtal
`of a battery or positive polarity of any other. sources of
`voltage. 2. The terminal
`to which the postuvc Side of
`the filament-voltage source of a vacuum tube should be
`connected.
`A power supply—HA power supply used as a source
`of heating current for the cathode or filament of a vacuum
`tube.
`apparatus— l. Any complex device. 2. Equipment
`or instruments used for a specific purpose.
`apparatus wire and cable—Insulated wire and
`cable used in connecting electrical apparatus to a power
`source. also including wire and cable used in the apparatus
`itself.
`apparent bearing—The direction from which the
`signal arrives with respect to some reference direction.
`apparent power— In an ac circuit. the power value
`obtained by simple multiplication of current by voltage
`with no consideration of the effect of phase angle.
`(Compare with true power.)
`apparent power
`loss—For voltage-measuring
`instruments.
`the product of nominal end-scale voltage
`and the resulting current. For current-measuring instru-
`ments. the product of the nominal end-scale current and
`the resulting voltage. For other types of instruments
`(for example. wattmcters).
`thc apparent power loss is
`expressed for a stated value of current or voltage. Also
`called volt-ampere loss.
`apparent source —See effective acoustic center.
`Apptegato diagram —A graphical representation of
`electron launching in a velocity-modulated tube. showing
`their positions along the drift space. This launching is
`plotted on the vertical coordinate. against time along the
`horizontal axis.
`applet—A small computer program that performs a
`simple task.
`ApplaTalk—A networking protocol developed by
`Apple Computer for communication between Apple Com-
`puter products and other computers. This protocol is inde-
`pendent of what network it is layered on.
`Appleton layer—In the ionosphere. a rcgiott of
`highly ionized air capable of reflecting or retracting radio
`waves back to earth. It is made up of the F. and F; layers.
`apple tuba —— A color-television picture tube in which
`the three colors of phosphors are laid in fine vertical strips
`along the screen. The intensity of the electron beam is
`modulated as its sweeps over them so that each color is
`produced with appropriate brightness.
`appliance—Any electrical equipment used in the
`home and capable of being operated by a nontcchnical
`person. Included are units that perform some task that
`could be accomplished by other. more difficult means.
`but usually not those used for entertainment (radios. TVs.
`hi-fl sets. elc.).
`appliance wire and cable—A classification of
`Undenvriters‘ Laboratories. Inc. covering insulated wire
`and cable intended for internal wiring of appliances and
`equtpment. Each construction satisfies the requirements
`for use in particular applications.
`application— 1. The use of a computer for a specific
`PUI'POSE. c.g.. designing a brochure er writing a letter.
`13351939 or problem to which a computer is applied.
`A",applt§:ation may be of the computational
`type.
`in
`winch al'llhIpCIic computations predominate. or of the
`dam-Processing type. in which data—handling operations
`Pmdonunate. See also application program.
`
`34
`
`I
`|
`
`application factor—~A modifier of the failure rate.
`is based on deviations from rated operating stress
`it
`(usually temperature and one clccu'ical parameter}.
`application-oriented language— I. A program.
`ming language that is primarily useful in some special-
`izcd area. 2. A problem-oriented programming language
`whose statements resemble or contain the terminology of
`the computer user.
`application program—1. A computer program
`intended to solve a problem or do a job. as distinct from
`systems programs. which control the operations of the
`computer system. 2. A computer program that perform a
`data-pmcessing function rather than a control operation.
`3. A program used to perform some logical or comm.
`tational
`task that is important to the user rather than
`some internal computer function. 4. Software designed for
`a specific purpose. such as accounts payable. inventory,
`payroll. and word processing. 5. A computer progrtun that
`accomplishes specific tasks. such as word processing.
`application schematic diagram—Pictorial rep-
`resentation using symbols and lines to illustrate the inter-
`relation of a number of circuits.
`application-Specific integrated circuit—See
`ASIC.
`applications software— 1. A program that depends
`on the specific end application and is used to do the
`real work or apparent work that is visible to the user.
`Generally this is the software that is used for dedicated
`computer-based systems (systems designed to perform a
`single or specific set of functions}. Typical applications
`include food and chemical processing. production con-
`trol. automotive electronics. computer—controlled sewing
`machines. photographic equipment (both for computer-
`conuollcd cameras and for darkroom computerized pro-
`cessing). energy distribution systems. word processing.
`mailing lists. payrolls. and inventory. 2. Computer pro-
`grams that perform specific tasks. such as word processing
`or database management.
`electrodes} — t. In
`applicators
`[applicator
`dielectric heating.
`the electrodes between which the
`dielectric item is placed and the electrostatic field
`developed. 2. Appropriately shaped conducting surl‘ao‘ls
`between which an altemating electric field is csrablishcd
`for the purpose of producing dielectric heating. 3; In
`medical electronics.
`the clccu‘odes applied to a pail-H3“I
`undergoing diathermy or ultrasonic therapy.
`applied voltage— 1. The potential between a to”
`minal and a reference point
`in any circuit or devrco
`2. The voltage obtained when measuring between 1‘”
`given points in a circuit with voltage applied to the 601]"
`plctc circuit. 3. The voltage presented to a circuit 90““
`or system input. as opposed to the voltage drop fwd"
`ing from current through an element that results from
`applied voltage.
`applique circuit—A special circuit providedI to
`|
`modify existing equipment in order to allow for some
`special usage.
`
`approach-control radar—Any radar set or 5F“;
`
`used in a ground-controlled approach system. 9-5"
`
`airport-surveillance radar. precision approach radar. 51:”
`
`approach path—In radio aircraft navigation. Ira
`
`portion of the flight path in the immediate vicinit)’ all”
`landing area where such a flight path terminates 9‘
`
`‘bIJ’
`touchdown point.
`_
`
`approved circuit—See protected wirelinc dtslfl
`tion system.
`APT—Abbreviation for automatically pro
`
`tool. a high-level or simplified programming languaf‘n.
`AQL—» Abbreviation for acceptable quality 18""
`
`'
`statistically defined quality level.
`in terms of
`f
`defective accepted on an average of 95 pence“1 °
`
`
`.
`
`I
`
`0004
`
`0004
`
`

`

`37
`
`or clamp—A fitting for gripping the armor of
`c at the point where the armor terminates or where
`e enters a junctioa box.
`.
`‘
`ilte Cab]
`and cable—Two or more insulated wires
`gnaw]? provided with a metallic covering. primarily
`collated the insulated wires front damage.
`"’ Pm strong frequency-modulation system—A
`“mm modulation system originally proposed by
`E EH. Armstrong.
`oscillator—An inductive
`feedback
`.
`'
`"0'19
`.
`m3; that consists of a tuned gate circuit and an
`oscifld tickler coil in the drain circuit. Feedback is con-
`fided by varying the coupling between the tickler and
`dug gate Clrctltl.
`
`llCKLEFl
`
`
`
`Armstrong oscillator.
`
`arr—See automatic repeat request.
`array—- 1. in an antenna, a group of elements arranged
`to provide the desired directional characteristics. These
`elements may be antennas. reflectors. directors. etc. 2. A
`series of items, not necessarily arranged in a meaning-
`ful pattern. 3. The group of patterns on a wafer or in the
`artwork or photomask for semiconductor processing. See
`random—access memory.
`array antenna — An antenna comprising a number of
`radiating elements, generally sirrtilar. arranged and excited
`to obtain directional effects.
`
`array device—A group of many similar. basic. com-
`plex. or integrated devices without separate enclosures.
`Each has at
`least one of its electrodes connected to a
`common conductor. or all are connected in series.
`. array noise—Unwanted disturbance in a memory
`Integrated circuit generated by the normal movement of
`data within the array.
`array processor— 1. A computer optimized itt
`architecture and instruction set to handle programs involv-
`"jg computations on large batches of data. such as last
`l‘tturter transforms and large matrix computations. An
`"mil processor takes blocks of data and instructions from
`it host mun or large computer and performs the computa-
`xiii)? tat: speeds. many times as high as those that are pos-
`Em};d “’33" the host computer alone. The host may be
`Star is ltip:
`the data-organizing front end: the array proces-
`desiin t: Pmlffcsstng utul. 2: ‘A computcrdedtcated by us
`“Il‘llltgrgc . P0 onnlng repetitive anthtnettcal .calculattons
`T-‘mge amt} of data With high precision. wide dynamic
`"Forniions
`1:ng throughput. Usually most Inputfoutput
`Clllnputer ian dhie management chores are left to the host
`C(Iucemmn or er to free the peripheral array processor to
`Operates. a: on tts_cnlculattons. 3. A single computer that
`a colflputer $39 Piece of data at a time. 4. A processor on
`lhan is d
`fill Performs matrix anthmettc much faster
`llt I 0
`-
`.
`_
`.
`one in a standard computer. Capable of perfum-
`mi... Ififitlons 011 all [he elements In large matrices at one
`.
`so called a vector processor.
`
`armor clamp — artificial intelligence
`
`arrester—Also called a lightning arrester. l. A pro-
`tective device used to provide a bypass path directly to
`ground for lightning discharges that strike an antenna or
`other conductor. 2. A power-lino device capable of reduc-
`ing the voltage of a surge applied to its terminals. inter-
`mpting current, if present. and restoring itself to original
`operating conditions. 3. Device that diverts high voltages
`to ground and away from the equipment it protects.
`ABEL—Abbreviation for American Radio Relay
`League.
`arrowhead—A linearly polarized. frequency-inde—
`pendent. log~pcriodic antenna.
`ARSR —Abbreviation for air route surveillance radar.
`AFlTCC—Abbreviau'on for air route traffic control
`center. A complex data-handling facility designed by
`Burroughs. IBM, and Raytheon to computerittc as much
`in—route air traffic control as possible.
`I. In
`articulation—Sometimes called intelligibility.
`a communications system,
`the percentage of speech
`units understood by a listener. The word articulation
`is customarily used when the contextual
`relationships
`among the units of speech material are thought to play
`an unimportant role; the word intelligibility is used when
`the context
`is
`thought
`to play an important
`role in
`determining the listener's perception. 2. A quantitative
`measurement of the intelligibility of human speech, where
`100 percent is completely understandable. For the typical
`sound reinforcement or other communications system. no
`more than a lS-percent articulation loss is acceptable.
`3. The ability of a mechanism to pivot. grasp. or extend.
`articulation
`equivalent —'l‘he
`articulation
`of
`speech reproduced over a complete telephone connection.
`expressed numerically in terms of the trunk loss of a
`working reference system that is adjusted to give equal
`articulation.
`artificial antenna—Also called dummy antenna.
`A device that simulates a real antenna in its essential
`impedance characteristics and has the necessary power-
`handling capabilities, but which does not
`radiate or
`receive radio waves. Used mainly for testing and adjusting
`transmitters.
`artificial ear—A microphone-equipped device for
`measuring the sound pressures developed by an earphone.
`To the earphone it presents an acoustic impedance equiv-
`alent to the impedance presented by the human ear.
`artificial echo— 1. Received reflections of a trans-
`mitted pulse from an artificial
`target. such as an echo
`box. corner reflector, or other metallic reflecting surface.
`2. A delayed signal from a pulsed radio—frequency signal
`generator.
`artificial horizon — A gyroscopically operated in strUm
`ment that shows. within limited degrees. the pitching and
`banking of an aircraft with respect to the horizon. Lines
`or marks on the face of the instrument represent the air-
`craft and the horizon. The relative positions of the two
`are then easily discernible.
`1. The
`artificial
`intelligence—Abbreviated AI
`design of computer and other data-processing machinery
`to perform increasingly higher-level cybernetic functions.
`2. The capability of a device to perform functions that
`are normally associated with human intelligence. such
`as reasoning. learning. and self-improvement. Related to
`machine learning. 3. The imitation by artificial systems
`of characteristics described as intelligent when observed
`in humans. Artificial intelligence embraces Concepts and
`theories from many different disciplines, including math-
`ematics. cybcmetics. computer science. psychology. biol~
`ogy. and others. 4. Overlapping subsets called expert
`systems, knowledge representations,
`inference schemes,
`program synthesis. scene analysis. and robotics. S. The
`ability of a machine to perform certain complex functions
`
`0005
`
`0005
`
`

`

`artificial ionization — aspect ratio
`
`normally associated with human intelligence, such as
`judgment. pattern recognition. understanding.
`learning.
`planning. and problem solving. 6. Computer programs
`developed to mimic human intelligence, such as reason-
`ing,
`learning, problem solving, and making decisions.
`Artificial intelligence programs enable computers to per-
`form tasks such as playing chess. proving mathematical
`theorems, etc. 7. An area of computer science dedicated to
`the development of machines that can learn. understand,
`interpret, and arrive at conclusions in a manner that would
`be considered intelligent if a person were doing it.
`artificial
`ionization—Introduction of an artificial
`reflecting or scattering layer into the atmosphere to permit
`beyond-dic-horizon communications.
`artificial
`language—In computer terminology, a
`language designed for ease of communication in a par-
`ticular area of activity, but one that is not yet natural to
`that area (as contrasted with a natural language evolved
`through long usage).
`artificial line—A lumpcd~constant network designed
`to simulate some or all the characteristics of a transmis—
`sion line over a desired frequency range.
`artificial Ilnc duct—A balancing network simulat-
`ing the impedance of the real
`line and distant terminal
`apparatus. It is employed in a duplex circuit to make the
`receiving device unresponsive to outgoing signal currents.
`artificial
`load—Also called dummy load. A dis-
`sipative but essentially nonradiating device having the
`impedance characteristics of an antenna,
`transmission
`line, or other practical utilization circuit. Energy is dissi-
`pated in the form of heat. Used to test radio transmitters,
`engine generators. etc. Permits testing under load con-
`ditions without the creation of any standing waves or
`radiating a signal.
`artificial radioactivity—Radioactivity induced in
`stable elements under controlled conditions by bombard-
`ing them with neutrons or high-energy, charged parti-
`cles. Artificially radioactive elements emit beta andloi'
`gamma rays.
`artificial voice—A small speaker mounted in a
`specially shaped baffle that
`is proportioned to simulate
`the acoustical constants of the human head. It is used for
`calibrating and testing close-talking microphones.
`Artos stripper—A machine that, when properly
`adjusted, will automatically measure to a predetermined
`length, cut. strip. count, and lie wire in bundles.
`ARTS—Abbreviation for Automated Radar Terminal
`System. A multiprocessor computing system used at
`terminal
`radar approach controls (tracons) and airport
`towers, based on Sperry Univac 1140 computers. Various
`configurations, differing in size of memory and number of
`processors, exist at different facilities; the largest, ARTS
`IIIE. is installed at the New York tracon.
`’artwork— l. A topological pattern of an integrated
`circuit, made with accurate dimensions so that it can be
`used in mask making. Generally, it is a large multiple
`of the final mask size, and final reduction is accom-
`plished through the use of a step-and-repeat camera.
`2. Detailed, original drawing [often developed with the
`31d of a computer) showing layout of an integrated cir-
`cuit. 3. The images formed by drawing. scribing. or by
`cutting and stripping on a film or glass support. which
`are reduced. contact-printed. or stepped and repeated to
`make a phototnnsk or intermediate. 4. Layouts and pho-
`tographic films created to produce thick-film screens and
`thin-him masks.
`_ASAv— Abbreviation For American Standards Associ-
`ation. See American National Standards Institute.
`A ASA code—.A code that was recommended by the
`mencan Standards Association for industry-wide use in
`the transmission of information. Now ANSI code.
`
`0006
`
`38
`
`asbestos—A nonflaminable material generally used
`for heat
`insulation. such as in a line-cord resistor. No
`longer used on new equipment.
`A-scan—Also called A-display. On a cathodcfly
`indicator. a presentation in which time {range or distance)
`is one coordinate (horizontal) and signals appear at
`perpendicular deflections to the time scale (vertical).
`‘
`
`IMPLITUUE
`
`-‘-II-
`
`
`IRANSMIHED
`PULSE
`
`
`
`RECEIVER NOISE
`
`tGRdSS}
`
`
`Milli!
`
`A-secn on a CRT.
`
`ASCII—Acronym for American Standard Code for
`Information Interchange (pronounced “ask-ee").
`l. A
`standard code used extensively in data transmission.
`in
`which 128 numerals. letters, symbols. and special control
`codes are each represented by a seven-bit binary num-
`ber 0000000 through 1111111. For example, numeral 5
`is represented by 01] 010i. letter K by 100 1011, percent
`symbol (96) by 010 0101, and start of text (STX) control
`code by 000 0010. 2. A standard code used by many com~
`puters, video-display terminals. teleprinters. and computer
`peripherals. A full eight-bit ASCII word may be trans-
`milled in parallel or serial form. with the eighth bit often
`providing parity information. Keyboard encoders convert
`a single switch closure into an ASCII data word: char-
`acter generators convert stored ASCII data words (and
`some liming commands) into groups of dots suitable for
`raster-scan display.
`A—scope—An oscilloscope that uses an A—scan to
`present
`the range of a target as the distance along a
`horizontal line from the transmitted pulse pip to the targcl»
`or echo pip. Signals appear as vertical excursions of the
`horizontal line, or trace.
`ASDE—See airport surface detection equipment-
`as-fired—Values of thick-film resistors or smoqlh'
`ness of ceramic substrates as they come out of the fil‘lnfa’
`furnace prior to trimming and polishing. respectively (lf
`required).
`ASl—An abbreviation for standards published by the
`American Standards Institute. New American National
`Standards Institute.
`ASlC—Abbrcvialion for application-specific ittlclim‘
`led circuit. 1. Semiconductor circuits specifically desiS'1te
`to suit a customer‘s particular requirement, as opposed '9
`general-purpose parts that can be used in many dil’fcrcfll
`systems or applications. 2. An integrated circuit deals“
`to fill the specific requirement of a unique application
`ask—See amplitude-shill keying.
`aspect ratio— l. Ratio of frame width to ltjfifl“
`height. 2. The ratio of an object's height
`to its “mm"
`In graphics this ratio usually pertains to the face Of a
`rectangular CRT or to the characters or symbols drawn hi
`the character generator. 3. The ratio between the lens1 I'
`of a film resistor and its width: equal to the number 0
`squares of the resistor. 4. The ratio of the width or a
`
`0006
`
`

`

`cellulose acetate -— centripetal force
`
`centi-—0ne hundredth (10—2) of a specific quantity
`or dimension.
`centigrade temperature scale —The older name
`for a Celsius temperature scale in the English-speaking
`countries. Officially abandoned by international agree—
`ment in l948. but still in common usage.
`centimeter waves—Microwave frequencies bet-
`ween 3 and 30 GHz, corresponding to wavelengths of
`10 to i centimeters.
`
`telephone
`central battery exchange—Manual
`exchange in which a battery situated at the exchange is
`the source of current for operating supervisory signals. for
`subscribers‘ calling signals, and for the current required
`to enable a subscriber to speak over his or her line.
`central office—The facility at which a communi-
`cations common carricr terminates customer lines and
`locates the equipment for interconnecting those lines.
`central-office equipment—Apparatus used in a
`telephone central office to furnish communication ser-
`VICES.
`central-office line—See subscriber line.
`central processing unit—Also called central pro-
`cessor; abbreviated CPU. 1. The part of a computer sys-
`tem that contains the main storage, arithmetic unit, and
`special register groups. Performs arithmetic operations.
`controls instruction processing. and provides timing sig-
`nals and other housekeeping operations. 2. A group of
`registers and logic that form the arithmeticl'logic unit plus
`another group of registers with aesociated decoding logic
`that form the control unit. Most MOS devices are single—
`chip CPUs, in that the registers hold as many bits as the
`word length of the unit. With bit-slice devices. however.
`central processing units of any bit width can be assembled
`essentially by connecting the bit—slice parts in parallel.
`Externally. a bit-slice device will appear to be a coherent
`single CPU capable of handling words of the desired bit
`length. 3. That part of a computer system that controls
`the interpretation and execution of instructions. In gen-
`eral, the CPU contains the following elements: arithmetic
`and logic unit (ALU), timing and control. accumulator.
`scratchqaad memory. program counter and address stack.
`instruction register, and U0 control logic. 4. That unit of a
`computing system that fetches, decodes. and executes pro-
`grammed instructions and maintains the status of results
`as the program is executed.
`central processorHSee central processing unit;
`CPU.
`central station—A control center to which alarm
`systems in a subscriber's premises are connected. where
`circuits are supervised and where personnel are main-
`tained continuously to record and investigate alarm or
`trouble signals. Facilities are provided for the reporting of
`alarms to police and fire departments or to other outside
`agencies.
`central station alarm system — An alarm system,
`or group of systems, the activities of which are transmitted
`to,
`recorded in, maintained by, and supervised from
`a central station. This differs from proprietary alarm
`systems in that the central station is owned and operated
`independently of the subscriber.
`centrax—l. A service offered by telephone cotn~
`panics. It uses central-office equipment to provide fea-
`tures comparable with those provided by a PBX. 2. An
`improved PBX system that also provides direct inward
`dialing (DID) and automatic number identification (ANI)
`of the calling PBX station.
`centrifugal force—The force that acts on a rotating
`body and that tends to throw the body farther from the
`axis of its rotation.
`centripetal force—The force that compels a rotat—
`ing body to move inward toward the center of rotation.
`
`_
`
`low-Power transmitters that allots-uninterrupted
`nicalions through sophisticated switching equip-
`1!"
`con "‘5’ king the cells. This system. by reusing frequencies
`men Imam-dial"? sci-vice and equipment. has substantially
`and 5“";d mobile telephone service.
`impriiiulose acetate—An inexpensive transparent
`l
`.[ic film used as the backing material for many record-
`? “b
`s.
`ingagwfilose-nitrate disc —See lacquer disc.
`Celsius temperature scete— Also called centri-
`9 temperature scale. A temperature scale based-on
`[reeling point of water defined as 0"‘C and the botltng
`Ill".
`UO‘C both under conditions of normal
`“It dcfiIth as l
`.
`fllm;.,-.phertc pressure {760 mm of mercury).
`cent-4‘ measure of frequency. defined as equal
`[0(th of n seinttone.
`_
`.
`center—fed antenna—43m antenna In which the
`feet-'16" wires are connected to the center of the radiator.
`center feed— 1. Attaching feeder wires or a trans-
`mission line to the center of the I‘ttdttltm‘ of an antenna.
`2. Connection of stgnal mput tertmnals to the center of
`a {fighter frequency—Also called resting frequency.
`L11“: average frequency of the emitted wave when
`modulated by a symmetrical signal. 2. The frequency at
`the center of a spectrum display (for linear frequency
`scanning}.
`It
`is usually tunable. 3. Also called free-
`mnning frequency. The frequency at which a phase-
`]ocltcd loop operates when not locked onto an incoming
`(input) signal.
`centering control—One of two controls used to
`Shift the position of the entire image on the screen of a
`cathode-ray tube. The horizontal—centering control moves
`the image to the right or left, and the vertical-centering
`control moves it up or down. See also framing control.
`centering diode—A clamping circuit used in some
`types of plan-position indicators.
`that centers the
`centering magnet—A magnet
`televised picture on the face of the tube. Also called
`framing magnet.
`center of gravity— A point inside or outside a body
`and around which all parts of the body balance each other.
`center of mass— On a line between two bodies. the
`point around which the two bodies would revolve freely
`as a system.
`center poise—Scale of viscosity for
`varnishes.
`center ring—-The part that supports the stator in
`an induction-motor housing. The motor end shields are
`attached to the ends of the center ring.
`center tap—A connection at the electrical center of
`a winding, or midway between the electrical ends of a
`resistor or other portion at a circuit.
`
`to
`
`insulating
`
`:3
`
`CENTER TAP
`
`Center rap.
`
`center-tapped inductor—An indttctor that has a
`lap at half the total inductance.
`center wire—A fine loop of wire used in propor-
`tional counters as an anode. A high voltage is applied to
`it to set the conditions for radiation measurement.
`center—zero meter—A dc meter that has its zero
`point at the center of the scale, e.g., a dc galvanometcr.
`
`0007
`
`0007
`
`

`

`class 0 insulating material - clock
`
`class 0 insulating material—An unimpregnated
`material or combination of materials, such as cotton. silk,
`or paper. Other materials or combinations of materials
`may be included if shown to be capable of satisfactory
`operation at lilD'C.
`class 3 amplifier— A pulse-width-modulated audio
`amplifier
`in which tltc active elements are switched
`by a control
`frequency several
`times higher than the
`signal frequency being amplified. Class S offers an ideal
`efficiency of 90 percent.
`clavleruAny keyboard, either hand or foot operated.
`clean room—A confined area in which the humid-
`ity. temperature. and particulate matter are precisely con-
`trolled within specificd units. The class designation of the
`clean room defines the maximum number of particles of
`(IS-micron size or larger that may exist in one cubic foot
`of space anywhere in the designated area. For example, in
`a Class 1 clean room. only one particle of any kind may
`exist in one cubic foot of space. Newer clean rooms are
`typically Class 1 to 10, and are needed for manufacturing
`ICs with feature size close to 1 micron.
`clear—1. Also called reset. To restore a storage or
`memory device to a prescribed or nonprogrammed stale.
`usually to zero or off (empty). 2. Remove all components
`of a calculation in a calculator. 3. In a calculator, to erase
`the contents of a display, memory, or storage register.
`4. As used in security work, the term clear is synonymous
`with reset. meaning that a latched circuit
`is restored
`to normal state. 5. Signal
`to reset or set all signals to
`an initial known state (usually zero). 6. The process of
`setting the contents of a register, flag, or memory location
`to zero. 7. To erase the contents of a display or a memory
`or storage register.
`clearance—The shortest distance through space
`between two live parts, between live parts and supports
`or other objects, or between any live part and grounded
`part.
`clear channel—In the standard broadcast band.
`a channel such that
`the station assigned to it
`is free
`of objectionable interference through all of its primary
`service area and most of its secondary service area.
`clear entry—Remove only the last number, not the
`entire calculation. in a calculator.
`clear entryl'clear all—In a calculator, a key used
`to clear the last entry or to clear the machine completely.
`clearing—l. Removal of a flaw or weak spot
`in
`the dielectric of a metallized capacitor by the electrical
`vaporization of the metallizied electrode at the flaw. 2. The
`ability of a lightning protector to interrupt follow current
`before the operation of circuit [uses or breakers. In the
`case of a simple gap, clearing frequently requires some
`external assistance.
`clearing ends—The operation of removing lhc
`sheath from the end of a cable. eliminating all moisture.
`and checking for crosses, shorts. and grounds in prepara-
`tion for testing.
`clearing—out drop—A drop signal associated with
`a cord or trunk circuit and operated by ringing current to
`attract the operator‘s attention.
`clear input—An asynchronous input
`used to set the Q output to logic zero.
`clear memory key—Removes what is stored in a
`memory register of a calculator.
`clear raster—A raster free of snow such as would
`be obtained in the absence of a video signal on either the
`cathodes or the grids of the three guns in the color CRT
`(mostly a function of bias conditions).
`clear terminal—Jae reset terminal.
`clear to send—See CTS.
`click—To point a mouse pointer at a word or icon
`on a monitor, press a mouse button. and then release it
`
`to a flip—flop
`
`i
`
`122
`
`quickly. Clicking is usually performed to select or deselect
`an item or to activate a program or a program feature.
`click and pop suppressor— An audio-signal-
`processing accessory. It removes or greatly reduces the
`audible transient sounds resulting from scratches and
`blemishes on the surface of a phonograph record.
`click filter—A capacitor and resistor connected
`across the contacts of a switch or relay to prevent a surge
`from being introduced into an adjacent circuit. See also
`key—click filter.
`click-noise modulation—A clipping action per.
`formed to increase the bandwidth of a jamming signal.
`Results in more energy in the sidebands, correspondingly
`less energy in the carrier. and an increase in the ratio of
`average power to peak power.
`client—A software program or computer that requests
`information from another computer.
`client-server network—A network that uses a
`central computer (server) to store data that
`is accessed
`from other computers on the network (clients).
`