differential amplifier common mode gain

Discussion in 'General Electronics Chat' started by f.h, Nov 16, 2014.

  1. f.h

    Thread Starter New Member

    Nov 16, 2014
    3
    0
    Why the common mode gain(Acm) in a real differential-amplifier is not zero?
    we have that Acm is 0 in an ideal differential amplifier but its not in real. why this happens?
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,234
    Because the devices in real circuits are not a perfect match and zero CM gain would require such a match.
     
  3. f.h

    Thread Starter New Member

    Nov 16, 2014
    3
    0
    yeah..but what happens then? i mean which current or voltages changes in comparison with ideal form?
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,234
    Depends entirely on the design of the particular differential amplifier circuit.
     
Loading...