base: see acids and bases acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water.
Properties
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(2) In a bipolar transistor, the elements that act as a switch. In NMOS and PMOS transistors, which make up CMOS circuits, the base is called the "gate." See transistor.
(3) A multiplier in a numbering system. In a decimal system, each digit position is worth 10x the position to its right. In binary, each digit position is worth 2x the position to its right.
base1
base2
base [bās]
Base
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base
In chemistry, any substance that in water solution is slippery to the touch, tastes bitter, changes the colour of acid-base indicators (e.g., litmus paper), reacts with acids to form salts, and promotes certain chemical reactions (e.g., base catalysis). Examples of bases are the hydroxides of the alkali metals and alkaline earth metals (sodium, calcium, etc.; see caustic soda) and the water solutions of ammonia or its derivatives (amines). Such substances produce hydroxide ions (OH−) in water solutions. Broader definitions of bases cover situations in which water is not present. See also acid-base theory; alkali; nucleophile.
base
(1) A starting or reference point.(2) In a bipolar transistor, the elements that act as a switch. In NMOS and PMOS transistors, which make up CMOS circuits, the base is called the "gate." See transistor.
(3) A multiplier in a numbering system. In a decimal system, each digit position is worth 10x the position to its right. In binary, each digit position is worth 2x the position to its right.
base1
1. a chemical compound that combines with an acid to form a salt and water. A solution of a base in water turns litmus paper blue, produces hydroxyl ions, and has a pH greater than 7. Bases are metal oxides or hydroxides or amines
2. Biochem. any of the nitrogen-containing constituents of nucleic acids: adenine, thymine (in DNA), uracil (in RNA), guanine, or cytosine
3. the inorganic material on which the dye is absorbed in lake pigments; carrier
4. Biology
a. the part of an organ nearest to its point of attachment
b. the point of attachment of an organ or part
5. Architect
a. the lowest division of a building or structure
b. the lower part of a column or pier
6. the lower side or face of a geometric construction
7. Maths
a. the number of distinct single-digit numbers in a counting system, and so the number represented as 10 in a place-value system
b. (of a logarithm or exponential) the number whose powers are expressed
c. (of a mathematical structure) a substructure from which the given system can be generated
d. the initial instance from which a generalization is proven by mathematical induction
8. Logic Maths the initial element of a recursive definition, that defines the first element of the infinite sequence generated thereby
9. Electronics the region in a transistor between the emitter and collector
10. Photog the glass, paper, or cellulose-ester film that supports the sensitized emulsion with which it is coated
11. a starting or finishing point in any of various games
12. Baseball any of the four corners of the diamond, which runners have to reach in order to score
base2
1. English history
a. (of land tenure) held by villein or other ignoble service
b. holding land by villein or other ignoble service
2. Music an obsolete spelling of bass
base [bās]
(chemistry)
Any chemical species, ionic or molecular, capable of accepting or receiving a proton (hydrogen ion) from another substance; the other substance acts as an acid in giving of the proton. Also known as Brønsted base.
(chemical engineering)
The primary substance in solution in crude oil, and remaining after distillation.
(computer science)
(electronics)
The region that lies between an emitter and a collector of a transistor and into which minority carriers are injected.
The part of an electron tube that has the pins, leads, or other terminals to which external connections are made either directly or through a socket.
The plastic, ceramic, or other insulating board that supports a printed wiring pattern.
(engineering)
Foundation or part upon which an object or instrument rests.
(genetics)
(graphic arts)
A transparent plastic film on which a photographic emulsion is applied.
(lapidary)
(mathematics)
A side or face upon which the altitude of a geometric configuration is thought of as being constructed.
For a logarithm, the number of which the logarithm is the exponent.
For a number system, the number whose powers determine place value.
For a topological space, a collection of sets, unions of which form all the open sets of the space.
(ordnance)
Station or installation from which military forces operate and from which supplies are obtained.
base
bases, 3
1. The lowest (and often widest) visible part of a building, often distinctively treated. A base is distinguished from a foundation or footing in being visible rather than buried.
3. Lower part of a column or pier, wider than the shaft, and resting on a plinth, pedestal, podium, or stylobate. Also see Asiatic base, Attic base.
4. A baseboard; skirting.
5. A preparation for a finished surface, as for flooring, stucco, paint, etc.; a surface to which the base coat of plaster is applied. Also see backing, ground.
6. In paint, either the medium or the main chemical ingredient.
7. In asphaltic or portland cement concrete paving, the prepared bottom course of crushed stone or gravel upon which subsequent courses are laid; serves to distribute localized wheel loads over a larger subbase and hence to improve load-bearing capacity.
8. The lowest point of any vertical pipe.
| (mathematics) | base - radix. |
Base
in electrical and radio engineering, a component of an electron or ion device, such as an incandescent lamp, a fluorescent lamp, or an electron tube. The base is used to install the device in, for example, a socket and to provide the connection between the elements within the device, such as the filaments or the electrodes, and the external electric circuit.
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