Glossary

AC

Alternating Current -- refers to a voltage or current that varies periodically with time

adder

Logic circuit whose output represents the sum of two or more inputs

address

Identification of the storage location of each piece of data or code in a computer memory

AI

See "artificial intelligence"

algorithm

Step-by-step method for solving a particular problem

ALU

Arithmetic/Logic Unit -- performs logic operations in a computer

AM

Amplitude Modulation -- information coding scheme involving changing the amplitude of a steady carrier wave

ammeter

Device for measuring current

ampere (amp) [A]1

Measure of electric current: 1 A = 1 coulomb/second

amplifier

Device whose output is a magnified replica of its input

analog

Characterizes a signal or device whose values are a continuous function of time (also see "digital")

AND

Logic gate whose output is binary 1 if all its inputs are 1's, and binary zero (0) otherwise (pronounced "and")

anode

In a vacuum tube, positively charged metallic electrode that attracts electrons produced by the cathode. In a solid-state diode the p-doped region which serves the same function.

angstrom [Å]

Measure of length: 1Å = 10^-10 m

antenna

Conductive structure to transmit or receive radio waves

application

Software system for a particular purpose, such as word processing (also see "program")

ARPANET

Computer network that developed into the Internet

artificial intelligence

Computer field that attempts to simulate human intelligence

ASIC

Application-Specific Integrated Circuit -- integrated circuit tailored to perform a very specialized function

assembler

Computer software that converts assembly language statements into machine language for execution

assembly language

Low-level programming language whose instructions closely correspond to machine language instructions

asynchronous

Operations that do not occur at a regular rate, in contrast to clocked synchronous operations

ATM

Asynchronous Transfer Mode -- a means for transmitting information on a network at very high rates

bandwidth

Frequency range over which a circuit or system operates

beta site

Location that tests a free version of hardware or software for a producer

binary

Numbering system based on powers of 2 using only the digits 0 and 1, called "bits"

BCD

Binary Coded Decimal -- numbering system using a 4-digit code to represent the decimal digits 0 to 9

bipolar- junction transistor

Transistor with n-type and p-type semiconductors having base-emitter and collector-base junctions

bit

a Binary digIT. See "binary"

BJT

See "bipolar-junction transistor"

Boolean logic

Logic operations -- such as AND, OR, NOT, and NAND -- based on only two logic states

buffer

Circuit that supplies an output to a load without affecting the input source; also, temporary storage medium

bus

Transmission medium for electrical or optical signals that perform a particular function, such as computer control

byte

A group of eight bits that can represent any of 2^8 = 256 different entities

cache

Circuitry with a small amount of high-speed memory to store frequently accessed microprocessor information

capacitance [F]

Characteristic of a capacitor: a 1-F capacitor charged to 1 V contains 1 C of charge (also see "capacitor")

capacitor

Energy storage circuit element having two conductors separated by an insulator

cathode

In a vacuum tube the metallic component which is heated to release electrons. In a solid state diode, the n-doped region which serve the same function.

CCD

Charge-Coupled Device -- imaging device with many field-effect capacitors that stores and moves packets of charge

CD

Compact Disk -- laser-read information storage device whose information is represented by microscopic pits

chip

Individual semiconductor circuit such as a memory or microprocessor (also known as a "die")

CISC

Complex Instruction-Set Computer -- microprocessor that executes variable-length instructions using complex addressing modes (also see "RISC") (pronounced "sisk")

clock

Unit that produces regularly occurring pulses to govern the operation of a computer

clone

Computer made by a different manufacturer patterned after an original design such as the IBM personal computer

CMOS

Complementary Metal-Oxide Semiconductor -- integrated circuit containing n-channel and p-channel MOSFETs (pronounced "sea-moss")

compiler

Program that converts a higher-level language program into machine language code

computer

Device that uses stored instructions and information to perform rapid computations or manipulate data

conductor

Material such as the metals copper or aluminum that conducts electricity via the motion of electrons

[C]

Measure of electrical charge: 1 C is an amount of charge equal to that of about 6.24 x 10^18 electrons

CPU

Central Processing Unit -- computer unit that interprets and carries out the stored instructions

CRT

Cathode Ray Tube -- special purpose vacuum tube used to produce images in oscilloscopes, televisions, and computer monitors. Operates by impinging a beam of high energy electrons into phosphors on the screen. Images are formed by deflecting the beam and modulating the intensity of the beam.

current [A]

Measure of rate of flow of electric charge: a one-ampere current is a flow of 1 C of charge per second

cutoff

Condition in a diode or bipolar junction transistor in which the potential across a p-n junction prevents current flow

decimal

Refers to numbering system based on power of 10

demodulator

Device that removes for use information coded by a modulator in electrical or optical form (also see "modulator")

design

To plan and delineate with an end in mind and subject to constraints

die

See "chip"

digital

Refers to systems employing only quantized (discrete) states to convey information (also see "analog")

diode

Two-terminal device that conducts current well in one direction and poorly in the other

DIP

Dual In-line Package -- common ceramic or plastic enclosure for an integrated circuit (pronounced "dip")

distribution

Refers to system for carrying electric power locally at voltages from 4 to 21 kV

DMA

Direct Memory Access -- data transfer between memory and I/O peripheral device without microprocessor intervention

doping

Process of introducing impurity atoms into a semiconductor to affect its conductivity

DOS

Disk Operating System -- operating system used especially on IBM computers (pronounced "doss")

DRAM

Dynamic Random Access Memory -- memory in which each stored bit must be refreshed periodically (pronounced "dee-ram")

DSP

Digital Signal Processor -- specialized IC system for processing real-time data such as sound or images

DUT

Device Under Test -- the device which is currently being tested.

electrical breakdown

Condition in which, particularly with high electric field, a nominal insulator becomes electrically conducting

electric field [V/m]

In simplest form, the potential difference between two points divided by the distance between the two

electromagnetic wave

Propagating wave having electrical and magnetic components; different frequencies are identified as radio waves, microwaves, infrared radiation, visible light, ultraviolet light, x-rays, gamma rays and cosmic rays.

electron

Elementary negative particle whose charge is -1.602 x 10^-19 coulombs

energy [J]

Capacity for performing work

engineering

Putting scientific knowledge to practical use

EPROM

Electrically Programmable Read-Only Memory -- nonvolatile memory device (pronounced "ee-prom"

Ethernet

Communication "party-line" for computers that features collision detection

extrinsic

Characterizes doped, rather than pure, semiconductor

fab

For "fabrication", a term referring to the making of semiconductor devices such as microprocessors

farad

The unit of capacitance (see "capacitance")

FET

Field-Effect Transistor -- semiconductor device whose insulated gate electrode controls current flow (may be pronounced "fet")

filament

In a vacuum tube, a wire which is heated by the flow of electrical current, that heats the cathode, the cathode material may be directly on the filament or an electrically isolated structure.

firmware

Computer software stored on a ROM chip

fiber-optic

Relates to transmission of information as modulated light in tiny transparent fibers instead of copper wires

finite-state machine

A style of logical construct having a limited number of internal states that, together with the external inputs, determine the next state

flip-flop

Binary device whose outputs change value only in response to an input pulse

foundry

Establishment that fabricates semiconductor devices for many different customers

floppy disk

Magnetic disk up to 5-1/4 inches across that stores data and computer programs

FM

Frequency Modulation -- information coding scheme in which the frequency of a steady wave is changed

frequency

Number of times per second that a quantity representing a signal, such as a voltage, changes state

FPU

Floating Point Unit -- integrated circuit for handling floating-point (non-integer) numbers

FTP

File Transfer Protocol -- protocol governing transfer of files between computers

full adder

Logic circuit that adds three input bits to produce sum and carry output bits

gate

Circuit whose logical output variables are determined by its inputs (also see AND, OR, NOT, NAND, NOR, XOR)

gauss

The cgs unit used in measuring magnetic induction

Gopher

Internet search program that uses a system of menus to assist in your search

ground

To make electrical connection to the earth or to the chassis of a device (verb); the connection point so used (noun)

GUI

Graphical User Interface -- hardware, software, and firmware that produces the display on modern personal computers (may be pronounced "gooey")

hexadecimal

Numbering system using base 16; representations are symbols 0, 1, ..., 9, A, B, ..., F

half adder

Logic circuit that adds two input bits to produce sum and carry output bits

hard disk

Storage device employing a rigid spinning disk coated with magnetizable material

hardware

Physical components of a computer system such as integrated circuits and circuit boards

henry

Unit of inductance (see "inductance")

Home Page

A site or "page" on the World Wide Web

hole

In a semiconductor, an absent electron that behaves as a mobile positive charge (also see "electron")

http

hypertext transfer protocol -- transfer protocol used on the World Wide Web

IC

See "integrated circuit"

IEEE

Institute of Electrical and Electronic Engineers -- largest association for workers in these fields (called I triple E)

impedance

Characteristic of circuit elements in AC circuits, analogous to resistance (also see "reactance")

inductance [H]

Characteristic of an inductor: in a 1-henry inductance a current change of 1 A per second produces an electromotive force of 1 V

inductor

Energy storage circuit component consisting of a coil of wire and possibly magnetic material

infrared

Invisible electromagnetic radiation having a longer wavelength, and lower frequency, than visible red light

instruction

Single command given to a computer's processor, such as ADD (add) or INR (increment)

insulator

Material that conducts electricity very poorly (also see "conductor", "semiconductor")

integrated circuit

Semiconductor circuit, typically on a silicon chip, containing microfabricated transistors and other circuit elements

Internet

Worldwide digital communication network in which packets of information travel between senders and recipients

interrupt

Signal that stops the operation of a microprocessor for servicing other hardware or software needs

intrinsic

Characterizes pure undoped semiconductor (also see "extrinsic")

inverter

Logic gate that converts a binary 1 to a 0, and a 0 to a 1 (also see "NOT")

I/O

Input/Output -- information transfer between computer and peripherals such as keyboard or printer (pronounced "eye-owe")

ISDN

Integrated Service Digital Network -- standard for transmitting at high rate over digital phone lines

kilobyte (KB)

2^10 (= 1024, or about one thousand) bytes of information

kilohertz (kHz)

One thousand cycles per second (see also "frequency")

LAN

Local Area Network -- digital communications network that serves users typically within less than a one-kilometer radius (pronounced "lan")

laser

Light Amplification by the Stimulated Emission of Radiation -- quantum device that produces coherent light

LCD

Liquid Crystal Display -- display device employing light source and electrically alterable optically active thin film

LED

Light-Emitting Diode -- semiconducting diode that produces visible or infrared radiation

logic design

Methodology of designing networks of logic gages to perform desired logic functions, as for computing purposes

loudspeaker

Device that produces sound when driven with an AC current

magnetic field strength (H) [A/m]

Magnetic field produced by a current, independent of the presence of magnetic material

magnetic flux [weber]

Magnetic induction per unit area

magnetic induction (B) [T]

Basic magnetic field vector, which includes effects of currents and magnetic materials

magnetron

Vacuum tube that produces microwave energy as electrons produced by a heated cathode move in a steady magnetic field in cylindrical paths past a surrounding anode.

mask

Pattern on glass, like a photographic negative, for producing integrated-circuit elements on semiconductor wafer

mean

Numerical average of data values

megabyte (MB)

2^20 (= 1,048,576, or about one million) bytes of information

megahertz (MHz)

One million cycles per second (see also "frequency")

MEMS

Micro ElectroMechanical System -- microscopic mechanical elements, fabricated on silicon chips by techniques similar to those used in integrated circuit manufacture, for use as sensors, actuators, and other devices (pronounced "mems")

meter

Tool for measuring (also see "ammeter", "multimeter", "ohmmeter", "voltmeter")

microphone

Device that produces voltage or current in response to a sound wave

microprocessor

Chip containing the logical elements for performing calculations and carrying out stored instructions

microwave

Electromagnetic wave whose frequencies range from roughly 1GHz to hundreds of GHz used in satellite communications, radar and microwave ovens.

microwave oven

Appliance for cooking in which a magnetron produces microwave electromagnetic energy that irradiates the contents and heats them by causing rapid movement of the water molecules they contain.

MIDI

Musical Instrument Digital Interface -- standard for transfers among computers and musical instruments (pronounced "middy")

mike

See "microphone"

MIPS

Millions of Instructions per Second -- a measure of computing power (pronounced "mips")

modem

Modulator-demodulator -- device for transmitting and receiving digital data over a transmission line

modulator

Device that changes a voltage, current, or light beam to encode information

monitor

Display unit employing a cathode ray tube (CRT)

Moore's law

After Gordon Moore: "The number of transistors per computer chip will double roughly every two years"

MOSFET

Metal-Oxide-Semiconductor Field-Effect Transistor -- device where gate electrode potential controls current flow (pronounced "moss-fet")

motherboard

Printed circuit board that contains the main circuits of a computer

multimeter

Tool for measuring several electrical quantities such as voltage, current, and resistance

multiplexer

Device for combining several signals or data streams into a single flow

multitasking

Ability of a computer to perform a number of functions at once, such as word processing and printing

multivibrator

Circuit that uses feedback to produce a repetitively changing output

mux

See "multiplexer"

n-type

Characterizes a semiconductor containing predominantly mobile electrons (also see "p-type")

NAND

NOT-AND -- logic gate whose output is the negation of that of the AND gate (pronounced "nand")

NOR

NOT-OR -- logic gate whose output is the negation of that of the OR gate (pronounced "nor")

NOT

Logic gate whose output is binary 1 when its input is 0, and whose output is a 0 when its input is a 1 (pronounced "not")

NTSC

National Television Standards Committee -- the broadcast standard developed in the United States, and used in Japan and Western Hemisphere countries.

ohm (W)

Unit of resistance (see "resistance")

ohmmeter

Tool for measuring electrical resistance

op-amp

Operational Amplifier -- semiconductor amplifier characterized by high gain and high internal resistance

operating system (OS)

Software that manages a personal computer, including the devices, process scheduling, and files

OR

Logic gate whose output is a binary 1 if any of its inputs is a 1; zero otherwise (pronounced "or")

oscillator

Circuit that produces an alternating voltage (current) when supplied by a steady (DC) energy source

p-type

Characterizes a semiconductor containing predominantly holes (also see "n-type")

package

Protective enclosure for a chip, typically made of plastic or ceramic

parallel port

A computer I/O port that transfers bits in parallel over a set of wires, as in a ribbon cable

PC

Personal Computer; Printed Circuit (also see "printed circuit board"); Program Counter

peripheral

Components that are adjunct to the microprocessor of a computer such as a disk drive or a printer

permeability [m]

From the relation between magnetic induction and magnetic field; for free space, m0 = 1.26 x 10^-6 H/m

permittivity [e]

From the relation between polarization charge and electric field; for free space, e0 = 8.85 x 10^-12 F/m

PDA

Personal Digital Assistant -- portable handheld computer for uses such as scheduling and taking notes

photodiode

Semiconductor diode that produces voltage (current) in response to illumination (also see "phototransistor")

photolithography

Process for forming integrated circuits involving photoemulsion spun on wafer, exposed with circuit layout, and then developed

phototransistor

Transistor that, when powered, produces amplified voltage (current) in response to illumination

pin-out

Diagram showing for electronic components the relations between connecting pins and internal components

pixel

Picture Element -- smallest element of an image, such as a dot on a computer monitor screen

polysilicon

Polycrystalline silicon used as conductor in integrated circuits, and especially FETs

power [W]

Product of voltage and current in a component; also, refers to the field of electric energy supply

printed circuit board

PC -- selectively metallized insulating sheet for supporting and interconnecting circuit components

program

Software written to perform a specific task, such as calculating student grades (also see "application")

radar

ra(dio) d(etection) a(nd) r(anging) -- use of transmitted and reflected radio waves to detect and measure motion of objects such as aircraft or thunderstorms (also see "sonar")

RAM

Random Access Memory -- read-write memory with elements accessible in any order (pronounced "ram")

reactance

Portion of impedance that characterizes non-dissipative, energy storage effects (also see "impedance")

rectifier

Device that converts bi-directional to one-way current flow

research

Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles

resistance [ohm]

Characteristic of a resistor: in a 1-ohm resistance a current of 1 A produces a voltage drop of 1 V

resistor

Energy dissipative element consisting of a poor conductor in series with connecting wires

RF

Radio Frequency -- refers to alternating voltages and currents having frequencies between 9 kHz and 3 THz

RISC

Reduced Instruction-Set Computer -- computer using fewer, simpler commands for faster processing (also see "CISC") (pronounced "risk")

rms

Root mean square.

ROM

Read-Only Memory -- memory whose elements can only be read but not altered (pronounced "rom")

saturation

Condition in an amplifier or BJT where the output is at an extreme value that is relatively independent of the value of the input. In FETs this word is used to describe the normal operating region.

science

A branch of knowledge concerned with establishing and systematizing facts, principles and methods, as by experiments and hypotheses

SCSI

Small Computer System Interface ("scuzzy") -- hardware that allows fast I/O devices to connect to a computer

semiconductor

Material, such as silicon, whose electrical conductivity is moderate and alterable by doping

serial port

A computer I/O port that transfers bits sequentially over a single wire

shift register

Information storage circuit permitting individual bits to be moved through in response to an external shift signal

silicon

Element 14 of the periodic table, basis for most integrated circuits

SIMM

Single In-line Memory Module -- circuit board containing memory chips for easily installation (pronounced "sim")

software

Computer instructions for operating in step-by-step fashion for problem solving

sonar

so(und) n(avigation) a(nd) r(anging) -- use of transmitted and reflected sound waves in water to detect and measure motions of objects such as fish and submarines (also see "radar")

speaker

See "loudspeaker"

standard deviation

A measure of the spread of data values. It is the root-mean-square (rms) of data point values with respect to the mean.

state table

For computer programs and sequential logic circuits, a table listing actions and new states for each current state and possible input

switch

Device that establishes (makes) or discontinues (breaks) a contact to one or more conductors

synchronous counter

Electronic circuit, for counting pulses, that is synchronized by a clock

technology

The practical or industrial arts, or applied science

Telnet

System allowing user to log into remote computers on Internet

tesla [T]

Unit of magnetic induction: 1 T = 1 weber/m2 (also, 1T = 104 gauss)

timing diagram

Graph of voltage (current) levels of a logic circuit as a function of time

transformer

Device using magnetically linked inductors to change AC voltage level

transmission

Refers to system for carrying electric power at voltages above 100,000 volts

transistor

Semiconductor device used for amplification and switching

truth table

Tabular summary of input-output relations for a logic gate

turn-on voltage

Applied voltage required to produce conduction in a diode (also see "diode", "bipolar junction transistor", "zener diode")

UNIX

Operating system used on workstations and many computer networks (pronounced "yew-nicks")

URL

Universal Resource Locator -- address of a World Wide Web site

Usenet

Interlinked bulletin boards available via Internet and commercial on-line services

UV

Ultraviolet -- characterization of short-wavelength light for exposing photoresist in making semiconductor devices

vacuum tube

Predecessor to the solid-state transistor and diode, an evacuated glass or metal enclosure containing a cathode which is heated to emit electrons and other electrodes for control of the flow and reception of those electrons. (also see "magnetron" and "CRT")

VCR

Video Cassette Recorder -- device that stores and retrieves magnetically recorded images and sound

virtual memory

Refers to use of magnetic disk memory to augment fast electronic random access memory (RAM)

virtual reality

Interface that delivers visual and audible outputs that mimic the real world

volt

Unit of electrical potential difference (see "voltage")

voltage [V]

Potential difference between two points: energy to move a 1-C charge through a 1-V potential difference is 1-J

voltmeter

Tool for measuring voltage (potential difference)

VR

See "virtual reality"

wafer

Semiconductor disk out of which integrated circuits are made (also see "chip", "mask")

WAN

Wide Area Network -- network composed of different transmission media covering large geographical area (pronounced "wan")

watt

Unit of power

weber

Unit of magnetic flux

World Wide Web

Graphical hypertext system linking many Internet computers

WYSIWYG

What You See Is What You Get -- characterizes software: what you see on the display is what you get on the printed output. (pronounced "wizzy-wig")

XOR

Exclusive OR -- logic gate whose output is 1 if any, but not all, its inputs are 1s; otherwise, zero (0) (pronounced "ex-or")

Zener diode

Semiconductor diode that has a well-defined turn-on voltage for conduction in the reverse direction