What is quiescent current?

Discussion in 'General Electronics Chat' started by sharath_412, May 17, 2007.

  1. sharath_412

    Thread Starter Active Member

    May 7, 2007
    32
    0
    Hi,
    What is quiescent current?
    Is it the current consumed by the device when there is no load( regulator)?
    Or is the definition based on the component used? for example regulators, Op amps etc.


    :)
     
  2. awright

    Well-Known Member

    Jul 5, 2006
    84
    7
    Your guess is correct. Quiescent current is the current drawn by a circuit when it is not amplifying a signal or driving a load (my definition, not an official definition).

    I(q) of a DC-DC converter would be the current it draws when there is no load on the output so it is functioning (i.e., generating the desired output voltage), but is not supplying current to a load.

    Same for an IC voltage regulator or an amplifier.

    Think of it as the baseline current required to have the device ready to perform its task.

    awright
     
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  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    213
    awright has stated the definition quite well.

    At the risk of repetition, quiescent current is that amount of current consumed from a power source by a single component or group of components in a circuit when the circuit is in its powered but non-operating state.

    hgmjr
     
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  4. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,179
    998
    quiescent
    Function: adjective
    Etymology: Latin quiescent-, quiescens, present participle of quiescere to become quiet, rest, from quies
    1 : marked by inactivity or repose : tranquilly at rest
    2 : causing no trouble or symptoms

    Definition 1 describes the quiescent condition of a circuit. Typically used in circuits when no drive signal is present.
     
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