One last one

Discussion in 'Homework Help' started by jamespierre, Dec 4, 2007.

  1. jamespierre

    Thread Starter New Member

    Dec 4, 2007
    6
    0
    The input voltage to a certain op-amp inverting amplifier is 10 mV, and the output is 2 V. What is the closed-loop voltage gain?

    How would I go about this as well?
     
  2. Distort10n

    Active Member

    Dec 25, 2006
    429
    1
    Impossible. Unless the amplifier is pegging to the positive rail because of some nefarious reason.

    Since it is inverting the output voltage would be -2V. An inverting amplifier has an ideal closed loop signal gain expressed as:

    Vout/Vin = -Rf/Rg

    You don't know the resistor values, but you know Vout and Vin so what is the gain?
     
  3. RiJoRI

    Well-Known Member

    Aug 15, 2007
    536
    26
    "Gain" is the relationship between input and output -- in this case voltage. It is shown in a fractional form (Vo/Vi), which can usually be reduced. (If Vi = 5 and Vo = 10,Av = 2).

    So, 2V/10mV will give you the gain: How much the signal has "gained" by passing through the amplifier.

    (Now if only I had a "money amplifier"! :D )
    --Rich
     
  4. jamespierre

    Thread Starter New Member

    Dec 4, 2007
    6
    0
    That made perfect sense! You should be a professor haha :)
     
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