§ 223. — Units of electrical measure.
[Laws in effect as of January 24, 2002]
[Document not affected by Public Laws enacted between
January 24, 2002 and December 19, 2002]
[CITE: 15USC223]
TITLE 15--COMMERCE AND TRADE
CHAPTER 6--WEIGHTS AND MEASURES AND STANDARD TIME
SUBCHAPTER V--STANDARDS OF ELECTRICITY
Sec. 223. Units of electrical measure
From and after July 21, 1950, the legal units of electrical and
photometric measurement in the United States of America shall be those
defined and established as provided in the following paragraphs.
Resistance-ohm
The unit of electrical resistance shall be the ohm, which is equal
to one thousand million units of resistance of the centimeter-gram-
second system of electromagnetic units.
Current-ampere
The unit of electric current shall be the ampere, which is one-tenth
of the unit of current of the centimeter-gram-second system of
electromagnetic units.
Electromotive force and electric potential-volt
The unit of electromotive force and of electric potential shall be
the volt, which is the electromotive force that, steadily applied to a
conductor whose resistance is one ohm, will produce a current of one
ampere.
Quantity-coulomb
The unit of electric quantity shall be the coulomb, which is the
quantity of electricity transferred by a current of one ampere in one
second.
Capacitance-farad
The unit of electrical capacitance shall be the farad, which is the
capacitance of a capacitor that is charged to a potential of one volt by
one coulomb of electricity.
Inductance-henry
The unit of electrical inductance shall be the henry, which is the
inductance in a circuit such that an electromotive force of one volt is
induced in the circuit by variation of an inducing current at the rate
of one ampere per second.
Power-watt
The unit of power shall be the watt, which is equal to ten million
units of power in the centimeter-gram-second system, and which is the
power required to cause an unvarying current of one ampere to flow
between points differing in potential by one volt.
Energy--joule; kilowatt--hour
The units of energy shall be (a) the joule, which is equivalent to
the energy supplied by a power of one watt operating for one second, and
(b) the kilowatt-hour, which is equivalent to the energy supplied by a
power of one thousand watts operating for one hour.
Intensity of light--candela
The unit of intensity of light shall be the candela, which is one-
sixtieth of the intensity of one square centimeter of a perfect
radiator, known as a ``black body'', when operated at the temperature of
freezing platinum.
Flux of light--lumen
The unit of flux of light shall be the lumen, which is the flux in a
unit of solid angle from a source of which is the intensity is one
candela.
(July 21, 1950, ch. 484, Secs. 1-11, 64 Stat. 369; Pub. L. 88-165, Nov.
4, 1963, 77 Stat. 299.)
Amendments
1963--Pub. L. 88-165 substituted ``candela'' for ``candle'' wherever
appearing.
