One last one

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

  1. jamespierre

    Thread Starter New Member

    Dec 4, 2007
    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
    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
    "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 )
  4. jamespierre

    Thread Starter New Member

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