In its effect on opposing a current and in resisting its formation it
differs from true resistance. The latter in diminishing current strength
absorbs energy and develops heat; spurious resistance opposes and
diminishes a current without absorption of energy or production of heat.
[Transcriber's note: "Spurious resistance" is now called reactance,
consisting of capacitive reactance and inductive reactance. The
combination of reactance and (Ohmic/true) resistance is called
impedance. The calculation of impedance requires complex algebra, not
just real values used in DC circuit analysis.]
Resistance, Steadying.
When arc lamps are connected in parallel or multiple arc a small
resistance coil is sometimes placed in series with each lamp for
steadying purposes. It reduces the percentage of variation of resistance
in each lamp, which may be caused by a change in the position of the
carbons.
Resistance, Swiss Unit of.
A unit constructed by the "Administration Suisse," based on the same
data as the Breguet and the Digney Units. (See Resistance, Digney Unit
of)
It is equal to 10.30 legal ohms.
Resistance, Thomson's Unit of.
A unit of resistance based on the foot and second.
It is equal to 0.3166 legal ohm.
Resistance, Unit.
Unit resistance is that of a conductor in which unit current is produced
by unit electro-motive force.
Resistance, Varley's Unit of.
The resistance of a standard mile of a special copper wire 1/16 inch
diameter.
It is equal to 25.33 ohms.
Resistance, Weber's Absolute Unit.
A metric system unit; (meter / second) * 1E7
It is equal to 0.9089 legal ohm.
Resonance, Electric.
A set of phenomena known as the Hertz experiments are grouped under this
title, which phenomena are incidents of and depend on the propagation of
electric waves through wires or current conductors, as well as through
the ether. Ordinarily a wire is only a seat of current, and is in its
nature inconsistent with wave propagation through its mass. Such waves
are virtually confined to the exterior of the wire. The point is that
the current-producing force is supposed to enter the wire at all points
from without, the current not being produced by an end-push. Hence in
rapidly recurring waves which are produced by a rapidly pulsatory or
alternating current, no time is afforded for the current-producing
force, in this case the wave-producing force, to penetrate into the
substance of the wire. In one of his experiments Dr. Hertz surrounded a
wire by a glass tube chemically silvered. The coating was so thin as to
be translucent. Through this metallic layer a current could be induced
in the wire in its interior. Any mechanical layer of metal took up the
induction itself, and protected the central wire. This gave a clue to
the thickness of metal penetrated by the rapid induced waves used by Dr.
Hertz.