CE amplifier

Discussion in 'Homework Help' started by hamza324, Nov 29, 2011.

  1. hamza324

    Thread Starter Member

    Jul 10, 2011
    33
    1
    hi i have a basic question related to op ams.

    In circuit analysis of op amps.....when is it possible to ignore the  r_o \ (output \ \  resistance)

    for calculation of  R_L

    because in some of the problems i solved for CE amps ...... r_o was included during some of the problems and it was ignored for some problems in calculation of  R_L
    Thanks
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
     r_o \ (output \ \  resistance) is reduced by the loop gain in a op amp with negative feedback, so for practical values of circuit and op amp open loop gain it typically is negligible. If you use the op amp in an open loop or positive feedback application, then you may need to consider it.
     
    hamza324 likes this.
  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The output resistance of an opamp reduces the max peak output voltage when the load current is fairly high.
    An output resistance of 100 ohms reduces the max peak output voltage 2.5V when the max peak output current is 25mA.
     
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