Votage Gain

Discussion in 'Homework Help' started by mo2015mo, Mar 10, 2014.

  1. mo2015mo

    Thread Starter Member

    May 9, 2013
    157
    1
    Hi my friends,, :)

    my question written in attached photo ,, Is this conclude right??
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,397
    497
    The top circuit is: Vout=-200*Vin

    Your bottom circuit is: Vout=-200*(Vin/3)

    Your interpretation is that Gain is reduced. My interpretation is that Gain is the same, Vin is reduced.

    The reason for my interpretation is that you did not change the circuit that provides the gain, so there is no reason for Gain to change. Your top circuit has amplifier sub circuit that provides Gain of -200. Your bottom circuit has the same amplifier sub circuit, so the Gain remains -200.
     
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  3. mo2015mo

    Thread Starter Member

    May 9, 2013
    157
    1
    Okay...new info. thanks for your interpretation shteii01,,,
     
  4. BytetoEat

    New Member

    Mar 5, 2014
    25
    5
    Hmm I disagree with shteii,

    The gain is reduced because we are talking in terms of Vin and Vout. Everything inbetween is the amplifier, which in the second circuit is 1/3rd of the first. Vin is 3mV in both cases, its not reduced..
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    4,804
    You have either modified the original amplifier circuit and reduced its gain by a factor of three, or you have inserted a gain stage that has a gain of 1/3. In either case, you total system gain has been reduced by a factor of three.
     
  6. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,397
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    I think I see your point. If we treat the voltage source as Vin, then from my own equation:
    Vout=-200(Vin/3)
    we get
    Vout=(-200/3)Vin
    so Gain is indeed -200/3.

    So basically we have attenuator in series with amplifier, and the effect is product of both applied to the input.

    Ok. I apologize for being a little dense about it. I guess I was so focused on the trees that I did not see the forest.
     
  7. BytetoEat

    New Member

    Mar 5, 2014
    25
    5
    Well it's not that you're wrong in any way.. because it's just the perspective you look at it like WBahn is saying.. I only said that cause usually we think of the overall circuit but you can also look at it like two amplifiers etc etc..
     
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