1.
analog signal: a electonic signal that carries information and varies smoothly with time
2.
binary system: system consisting of two digits, 0 and 1 that can be used by devices such as computers to store or use information
3.
computer software: any list of instructions for computer to follow that is stored in the computer's memory.
4.
crystal: a solid substance which has a regularly repeating internal arragement of atoms
5.
digital signal: electronic signal that varies information that does not vary smoothly with time, but changes in steps between certain values and can be represented by a series of numbers
6.
diode: a solid state component made from two layers of semiconductor material that allows electric current to flow in only one direction and is commonly used to change alternating current to direct current
7.
electronic signal: a changing electric current that carries information
8.
intergrated circuit: circuit that can contain millions of interconnected transistors and diodes imprinted on a single small chip of semiconductor material
9.
laser: device that produces a concentrated beam of light
10.
microprocessor: integrated circuit that controls the flow of information between different parts of the computer; also called the central processing unit or CPU
11.
random-access memory: temporary electronic memory within a computer
12.
read-only memory: electronic memory that is permanently stored within a computer
13.
semiconductor: element such as silicon, that is a poorer electrical conductor that a metal but a better conductor than a non metal and whose electrical conductivity can be changed by adding impurities
14.
transistor: a solid state component made from three layers of semiconductor material that can amplify the strenght of an electric signal or act as an electronic switch
15.
vacuum tubes: early computers used vacuum tubes rather than integrated circuits
