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Glite Dictionary
time constant

time constant

3 7.0
The time in a circuit for the voltage or current to change by about 63 percent
  • noun
  • /taɪm ˈkɒnstənt/
  • Specialized
translation icon : constante de tiempo
  • So associated with that circuit is the time constant Tau, which is simply RC.
  • time constant filter
  • thermal time constant
  • decay time constant

Examples

  • The electrical time constant is 1.0 millisecond; the mechanical time constant is 19.2 milliseconds.

    Academic text (1995)

  • The linear filter was a low-pass filter with a time constant of 80 ms.

    Academic text (1992)

  • For these reasons, one expects the thermal time constant to be extremely long.

    Academic text (1995)

  • Now if if this is decaying so fast, that one time constant is sort of like this, right?

  • In a subsequent reply to comments, he arrives at a time constant of 10 years.

    Blog text (27)

  • Conversely, a low thermal time constant will cause the rotors to lose heat quickly.

    Academic text (1994)

  • The vestibulo-ocular reflex gain and dominant time constant decrease with age.

    Academic text (1999)

  • One apparent disadvantage of not having iron in the rotor is the short thermal time constant.

    Academic text (1994)

  • The linear filter was a low-pass filter with a time constant of 80 ms.

  • The electrical time constant is 1.0 millisecond, which affects the circuit's response rate.

Surface Forms

time constant singular
time constants plural

Morphology

time + constant

The phrase 'time constant' is partially transparent because combining 'time' and 'constant' conveys the idea of a fixed or characteristic amount of time, so a learner who knows both words can infer a general sense (a specific, stable time related to a process). However, the precise technical meaning used in electronics — the ~63% change rule and its role in circuit behaviour — is specialised and not derivable from the constituents alone, so full understanding requires domain knowledge despite cross‑linguistic cognates.

Etymology

Time constant is a scientific phrase that names a fixed amount of time (a constant) used to show how fast a voltage or current changes. Imagine you start a change; after one time constant the change is about 'two-thirds' done, so the term now means the fixed time that tells how quickly a circuit or system reacts.