Question about transconductance gain of an amplifier.

Discussion in 'General Electronics Chat' started by tadm123, Mar 29, 2014.

  1. tadm123

    Thread Starter Member

    Nov 20, 2013
    As I understand it the intrinsic gain of an op amp is the open loop gain, and the overall gain is the closed loop gain with feedback.

    But my question is, what exactly is the transconductance gain? Is that the intrinsic gain of the amp? And if it isn't, how can I calculate the gain of the amplifier itself?

    I hope the question makes sense, thanks in advance.
  2. #12


    Nov 30, 2010
    Transconductance? Change in current for change in voltage? Operational amplifiers are voltage driven. They supply as much current as the load needs, within the limitations of the current the chip can deliver. If you want transconductance, you can get a transconductance amplifier that looks very much like an operational amplifier but works according to your expectations.
    tadm123 likes this.
  3. LvW

    Active Member

    Jun 13, 2013
    Yes - as indicated already by #12, there are some integrated amplifiers which - sometimes - are called "operational amplifier", although this is somewhat misleading.
    At first, there is the "operational transconductance amplifier" (OTA) which is voltage-driven with a current output.
    Hence: output/input=current/voltage=transconductance.
    By the way: This also applies to transistors which are characterized by their "transconductance" which is identical to the slope of the Ic=f(Vbe) characteristic.
    (The term "transconductance gain" is not correct).
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