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NATURE AND ORIGIN OF TRANSIENTS. 5

change of the stored energy, of whatever form this energy may be,
leads,to a transient.

Electrical transients have been studied more than transients of
other forms of energy because:

(a) Electrical transients generally are simpler in nature, and
therefore yield more easily to a theoretical and experimental
investigation.

(6) The theoretical side of electrical engineering is further
advanced than the theoretical side of most other sciences, and
especially:

(c) The destructive or harmful effects of transients in electrical
systems are far more common and more serious than with other
forms of energy, and the engineers have therefore been driven by
necessity to their careful and extensive study.

4. The simplest form of transient occurs where the effect is
directly proportional to the cause. This is generally the case in
electric circuits, since voltage, current, magnetic flux, etc., are
proportional to each other, and the electrical transients therefore
arc usually of the simplest nature. In those cases, however,
where this direct proportionality does not exist, as for instance in
inductive circuits containing iron, or in electrostatic fields exceed-
ing the corona voltage, the transients also are far more complex,
and very little work has boon done, and very little in known, on
theses more complex electrical transients.

Assume that in an electric circuit we have a transient cur-
rent, as represented by curve i in Fig. 4; that is, some change of
circuit condition requires a readjustment of the stored energy,
which occurs by the flow of transient current i Tim current
starts at the value ?*t, and gradually dies down to ssoro. Assume
now that the law of proportionality between cause and effect
applies; that is, if the transient current started with a different
value, %, it would traverse a curve ?/, which is the same as curve
i, except that all values are changed proportionally, by the ratio

$; that ta, t'=iX^-
ti' ti

Starting with current ti, the transient follows the curve i;
starting with i*, the transient follows the proportional curve i'.
At some time, t_f however, the current i has dropped to the value %,
with which the curve i' started* At this moment f, the conditions
in the first ease, of current i, are the same as the conditions in



	NATURE AND ORIGIN OF TRANSIENTS. 5 change of the stored energy, of whatever form this energy may be, leads,to a transient. Electrical transients have been studied more than transients of other forms of energy because: (a) Electrical transients generally are simpler in nature, and therefore yield more easily to a theoretical and experimental investigation. (6) The theoretical side of electrical engineering is further advanced than the theoretical side of most other sciences, and especially: (c) The destructive or harmful effects of transients in electrical systems are far more common and more serious than with other forms of energy, and the engineers have therefore been driven by necessity to their careful and extensive study. 4. The simplest form of transient occurs where the effect is directly proportional to the cause. This is generally the case in electric circuits, since voltage, current, magnetic flux, etc., are proportional to each other, and the electrical transients therefore arc usually of the simplest nature. In those cases, however, where this direct proportionality does not exist, as for instance in inductive circuits containing iron, or in electrostatic fields exceed- ing the corona voltage, the transients also are far more complex, and very little work has boon done, and very little in known, on theses more complex electrical transients. Assume that in an electric circuit we have a transient cur- rent, as represented by curve i in Fig. 4; that is, some change of circuit condition requires a readjustment of the stored energy, which occurs by the flow of transient current i Tim current starts at the value ?t, and gradually dies down to ssoro. Assume now that the law of proportionality between cause and effect applies; that is, if the transient current started with a different value, %, it would traverse a curve ?/, which is the same as curve i, except that all values are changed proportionally, by the ratio $; that ta, t'=iX^- ti' ti Starting with current ti, the transient follows the curve i; starting with i, the transient follows the proportional curve i'. At some time, t_f however, the current i has dropped to the value %, with which the curve i' started* At this moment f, the conditions in the first ease, of current i, are the same as the conditions in