IEVref:103-05-26ID:
Language:enStatus: Standard
Term: time constant
Synonym1:
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Symbol: τ
Definition: time τ in the expression F(t)=A+B e t/τ MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaiqaciWacmGadaGadeaabaGaaqaaaOqaaiaadAeacaGGOaGaam iDaiaacMcacqGH9aqpcaWGbbGaey4kaSIaamOqaKqzafGaciyzaOWa aWbaaSqabeaacqGHsislcaWG0bGaai4laiaads8aaaaaaa@419A@ of a quantity F growing or decaying exponentially towards a constant value A with increasing time t, or in the expression F(t)=A+f(t) e t/τ MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGe aGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaq Fn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpe WZqaaiqaciWacmGadaGadeaabaGaaqaaaOqaaiaadAeacaGGOaGaam iDaiaacMcacqGH9aqpcaWGbbGaey4kaSIaamOzaiaacIcacaWG0bGa aiykaKqzafGaciyzaOWaaWbaaSqabeaacqGHsislcaWG0bGaai4lai abes8a0baaaaa@4489@ of an exponentially damped oscillation, where f is a periodic function of time

Note 1 to entry: The time constant of an exponentially varying quantity is the duration of a time interval at the end of which the absolute value of the difference between the quantity and the limit has decreased to 1/e of the absolute value of this difference at the beginning of the time interval, where e is the base of natural logarithms.

Note 2 to entry: The time constant of a damped oscillation is the inverse of the damping coefficient.


Publication date:2009-12
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Internal notes:2017-02-20: Editorial revisions in accordance with the information provided in C00020 (IEV 103) - evaluation. JGO
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