| A | B |
|---|
| circuit board | a collection of hundreds of tiny circuits that supply electric current to the various parts of an electronic device |
| doping | the process of replacing a few atoms of a semiconductor with a few atoms of another substance that have a different number of valence electrons |
| semiconductor | a substance that conducts electric current better than an insulator but not as well as a conductor |
| diode | an electronic component that allows electric current in only on direction |
| transistor | an electronic component that can be used as an amplifier or a switch |
| integrated circuit | an entire circuit containing many transistors and other electronic components formed on a single silicon chip |
| signal | something that represents information, such as a command, a sound, or a series of numbers and letters |
| telecommunications | the sending of information across long distances by electronic means |
| analog signal | a signal whose properties, such as amplitude and frequency, can change continuously according to changes in the original information |
| binary | two; binary numbers contain only the digits 1 and 0 |
| digital signal | a series of electrical pulses that represents the digits of binary numbers |
| electromagnetic wave | a wave that can travel through space or matter and consists of changing electric and magnetic fields |
| cathode-ray tube | (CRT) a special vacuum tube in which a beam of electrons is projected onto a screen |
| computer | an electronic device that performs tasks by processing and storing information |
| input | the information given to a computer |
| memory | the location where a computer stores information |
| output | the result of processing that is the final result or the proof of the task performed by a computer |
| microprocessor | an integrated circuit that contains many of a computer's capabilities on a single silicon chip |
| central processing unit | (CPU) the physical area in which a computer performs tasks |
| halogens | the elements in Group 17 of the periodic table; they are very reactive nonmetals, and their atoms have seven electrons in their outer level |
| hardware | the parts or equipment that make up a computer |
| input device | a piece of hardware that feeds information to the computer |
| bit | the name for each of the digits in a binary number |
| byte | a unit in which computers store and process information; equal to eight bits |
| modem | a piece of computer hardware that allows computers to communicate over the telephone lines |
| output device | a piece of hardware on which a computer shows the results of performing a task |
| RAM | (random-access memory) computer memory that stores information only while that information is being used |
| ROM | (read-only memory) computer memory that cannot be added to or changed |
| software | a set of instructions or commands that tells a computer what to do; a computer program |
| Internet | a huge computer network consisting of millions of computers that can all share information with one another |
