Coatings of a Condenser or Prime Conductor.
The thin conducting coatings of tinfoil, gold leaf or other conducting
substance, enabling the surface to receive and part with the electric
charge readily. Without such a coating the charge and discharge would be
very slow, and would operate by degrees only, as one part of a
non-conducting surface might be densely charged and another part be
quite devoid of sensible charge.
Code, Cipher.
A code of arbitrary words to designate prearranged or predetermined
words, figures or sentences. The systems used in commerce have single
words to represent whole sentences or a number of words of a sentence.
This not only imparts a degree of secrecy, but makes the messages much
shorter. Codes are used a great deal in cable transmission.
Code, Telegraphic.
A telegraphic alphabet. (See Alphabets, Telegraphic.)
Coefficient.
In algebra, the numerical multiplier of a symbol, as in the expression
"5x," 5 is the coefficient. In physics, generally a number expressing
the ratio or relation between quantities, one of which is often unity,
as a standard or base of the set of coefficients. Thus the coefficient
of expansion by heat of any substance is obtained by dividing its volume
for a given degree of temperature by its volume at the standard
temperature as 0º C., or 32º F. This gives a fraction by which if any
volume of a substance, taken at 0º C., or at whatever may be taken as
the basic temperature, is multiplied, the expanded volume for the given
change of temperature will be obtained as the product. A coefficient
always in some form implies the idea of a multiplier. Thus the
coefficient of an inch referred to a foot would be 1/12 or .833+,
because any number of inches multiplied by that fraction would give the
corresponding number of feet.
[Transcriber's note: 1/12 is 0.0833+]
Coefficient, Economic.
In machinery, electric generators, prime motors and similar structures,
the number expressing the ratio between energy absorbed by the device,
and useful, not necessarily available, work obtained from it. It is
equal to work obtained divided by energy absorbed, and is necessarily a
fraction. If it exceeded unity the doctrine of the conservation of
energy would not be true. The economic coefficient expresses the
efficiency, q. v., of any machine, and of efficiencies there are several
kinds, to express any one of which the economic coefficient may be used.
Thus, let W--energy absorbed, and w = work produced ; then w/W is the
economic coefficient, and for each case would be expressed numerically.
(See Efficiency, Commercial--Efficiency, Electrical--Efficiency of
Conversion.)
The distinction between useful and available work in a dynamo is as
follows: The useful work would include the work expended by the field,
and the work taken from the armature by the belt or other mechanical
connection. Only the latter would be the available work.