Output impedance of an amplifier

Discussion in 'General Electronics Chat' started by zamansabbir, Feb 22, 2009.

  1. zamansabbir

    Thread Starter Member

    May 27, 2008
    Why should be the output impedance of an amplifier should be kept small....is there any cause rather than power loss?
  2. Cabwood


    Feb 8, 2009
    The output of an amplifier will be supplying current to the next stage, whatever that may be. The output voltage will have been carefully prepared by the amplifier, to some known value, and you don't want the next stage to load the amplifier so heavily that it modifies that nice clean carefully constructed output voltage.

    Therefore, the amplifier's output impedance should be small enough to supply whatever current the next stage requires, while maintaining the voltage at the intended value.

    The lower the output impedance of an amplifier, the more it is able to provide the intended output voltage under load.
  3. Audioguru

    New Member

    Dec 20, 2007
    An audio amplifier has an output impedance of 0.04 ohms or less at low frequencies. The very low impedance damps speaker resonances.