Opamp Feedback problem, Urgent !!

Discussion in 'The Projects Forum' started by jaiminajmeri, Sep 4, 2013.

  1. jaiminajmeri

    Thread Starter New Member

    Sep 4, 2013
    1
    0
    Opamp Feedback problem, Urgent !!

    C1.jpg

    1) At resistor R3, Voltage at R3 is 5V initially.
    But, After the feedback this voltage changes to 500mV. Can somebody explain this with equations ?

    see the ckt here : http://imageshack.us/a/img163/1629/v3hq.jpg

    ----------------------------

    C2.jpg

    2) If I replace Voltage@ R3(5V) with 5V battery, then after feedback the voltage remains 5V itself, Any reason ?

    see the ckt here : http://imageshack.us/a/img35/3219/a9nc.jpg
     
  2. #12

    Expert

    Nov 30, 2010
    16,337
    6,820
    1) input voltage higher than supply voltage = broken amplifier.
    2) battery voltage + output of broken amplifier/1000 ohms = battery voltage
     
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