# transient

(redirected from transience)
Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.

## transient

Physics a brief change in the state of a system, such as a sudden short-lived oscillation in the current flowing through a circuit

## Transient

(or transient phenomenon). A transient in an electric circuit is a phenomenon that occurs during a transition from one circuit condition to another that differs from the initial condition in the amplitude, phase, shape, or frequency of the voltage acting in the circuit, the values of the parameters, or the configuration of the circuit. Transients occur chiefly when circuit elements are switched into or out of the circuit. The transients arise because the current flowing through an inductance and the voltage across a capacitance cannot be altered abruptly—that is, the energy of the electric and magnetic fields in the circuit’s capacitive and inductive elements cannot be changed instantaneously.

Theoretically speaking, a transient continues for an indefinite period because the voltage and current in an electric circuit after the closing or opening of a switch approach their final (steady-state) values asymptotically. In electrical engineering, however, a transient is considered to be ended when the voltage and current reach values differing from the steady-state values by 5 to 10 percent, a condition that occurs within a comparatively short finite interval of time. An electric circuit that is characterized by constant or periodically varying currents and voltages is said to be in a steady-state condition.

A simple example of a transient is the charging of a capacitor C (Figure 1) from a DC source (a storage battery) having an electromotive force (emf) E and an internal resistance r through a resistor R, which limits the current in the circuit. If the switch is closed at the time t = 0, the current in the circuit decreases according to an exponential law and approaches zero. Simultaneously, the voltage increases and approaches asymptotically the value of the source emf. The rate of change of the voltage and the current depend on the capacitance of the capacitor and the resistance in the circuit: the larger the capacitance and resistance, the longer the duration of the charging process. After a time interval τ = (R + r)C, called the time constant for the charging of the capacitor, the voltage across the capacitor’s plates attains the value uc = 0.6327, and the current i reaches 0.37I0, where I0 is the initial current. I0 is equal to the ratio of the emf and the resistance in the circuit. After a time interval of 5τ;, UC > 0.99E and i < 0.01I0; with an error of less than 1 percent, the transient can be regarded as having ended. During the transient, the energy of the capacitor’s electric field is increased from zero to Wc = CE2/2.

During a transient, in individual parts of a circuit there may occur voltage surges and overcurrents—that is, voltages and currents substantially greater than the steady-state voltages and currents. When equipment is not selected properly, the voltage surges can result in the breakdown of insulation in, for example, capacitors, transformers, and electrical machines. Overcurrents can cause the actuation of protective devices and the disconnection of equipment; they can burn out instruments, burn contacts, and cause mechanical damage to windings as a result of electro-dynamic stresses. Transients play an exceptionally important role in automatic control systems, pulse engineering, computer technology, measurement technology, electronics, radio engineering, and power engineering.

### REFERENCES

Neiman, L. R., and K. S. Demirchian. Teoreticheskie osnovy elektrotekhniki, vol. 1. Leningrad, 1967.
Ginzburg, S. G. Metody resheniia zadach po perekhodnym protsessam ν elektricheskikh tsepiakh, 3rd ed. Moscow, 1967.
Venikov, V. A. Perekhodnye elektromekhanicheskie protsessy ν elektricheskikh sistemakh. Moscow, 1970.
Teoreticheskie osnovy elektrotekhniki, part 1. Moscow, 1972.
Bessonov, L. A. Teoreticheskie osnovy elektrotekhniki. Moscow, 1973.

B. IA. ZHUKHOVITSKII

## transient

[′tranch·ənt]
(physics)
A pulse, damped oscillation, or other temporary phenomenon occurring in a system prior to reaching a steady-state condition.

## transient

1. <electronics> A sudden, brief increase in current or voltage in a circuit that can damage sensitive components and instruments.

## transient

A malfunction that occurs at random intervals and lasts for a short duration such as a spike or surge in a power line or a memory cell that intermittently fails. See spike and power surge.
References in periodicals archive ?
6) And although not a perfectly consistent finding because of the relatively few "durable" technologies, the overall historical record of technology transience has been one that has experienced steadily decreasing lifespans over the historical time frame.
Assuming these risk factors are interrelated and increase risk for illegal behaviors (Baron, 2009), we speculated that length of time homeless will indirectly predict arrest activity, as mediated through transience, substance use disorder, and survival strategies.
Second, such a beautiful spring helps remind us of the transience inherent in life, including recessions, and provides us with cheap entertainment, particularly important in the current economy.
Summary: Transience is integral to Beirut's material culture.
The results revealed that simply associating a smiley with less transience (coloring with a superfine micro tip, which takes a long time to color, rather than a sharpie, which colors the face in a few short strokes) resulted in people becoming more likely to act their long-term interests and choose an apple as a snack rather than a chocolate," write the authors.
This voice is attuned to die vagaries of power and the transience of military and political control.
The initial stage, covering the first five chapters of the book (starting at 1:12), is characterized by frustration with the transience of life: Kohelet bemoans the fact that all achievements are short-lived.
Das Lied set German translations of six Chinese lyric poems on the overall theme of the transience of life and its pleasures.
This poet/artist depicts homes lost in the mists of immense foothills, small figures wandering through rolling valleys, the transience of roads and buildings with the permanence of their natural surroundings.
War and War is only the second Krasznahorkai novel to be translated into English, following The Melancholy of Resistance (also translated by George Szirtes--excellent with everything but cursing and computers--and brought out in America by New Directions six years ago), but even with just this meager evidence to hand, the power and substance of Krasznahorkai's prose, its quality both of familiarity (qua Thomas Bernhard) and fundamental peculiarity (those epic, sinuous, mocking, endlessly associative sentences), is such that his Anglophone readers are bound to feel that he's already a major force--and long established--in our literature: this eras standard-bearer for a tradition of transience, skepticism, and negation.
He said: "The fluidity, changeability of relationships and the transience of marriage may look perfectly fine if you belong to the commentating classes of North London but you don't have to go many miles to see what the cost is for people who cannot take that sort of thing for granted.
PURCHASE, NY -- Popular for hundreds of years, still life paintings containing arrangements of inanimate natural objects, such as fruits, game, vegetables and flowers, and manmade objects, such as books, pipes, cutlery, and porcelain, were used often as symbolic reminders of life's transience, or by the artist solely to explore color, texture, and composition.

Site: Follow: Share:
Open / Close