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Homework Help: Summing Amplifier Question!

  1. Feb 16, 2012 #1
    1. The problem statement, all variables and given/known data

    Please refer to attached image!

    2. Relevant equations

    Absolutely no idea how to start this problem!

    3. The attempt at a solution

    A) I would think that there are 4 input combinations for this circuit.

    B) 0110 = 6v?

    C) No clue

    D) 1011 = 11v?

    E) No clue

    Attached Files:

  2. jcsd
  3. Feb 16, 2012 #2
    Part C is simple, the input is given in sin(2*pi*f*t). Just plug n chug to find f.
  4. Feb 16, 2012 #3
    How is the input given in sin(2*pi*f*t)??
  5. Feb 16, 2012 #4
    It's a standard way of writing AC voltage or current, sin(2∏ft) or sin(ωt), cos (ωt)
    I don't really know why it is this way.
  6. Feb 16, 2012 #5
    But the problem vs(t) = sin(4000pit)

    So ω = 4000?

    2pi*f*t = 4000*pi*t

    so f = 2000hz?
  7. Feb 16, 2012 #6
  8. Feb 16, 2012 #7
    Cool -thanks.

    How about Part D?
  9. Feb 16, 2012 #8
    It's a summing amplifier. When one input is grounded, contribution from that branch is zero.
    For the other inputs, since 3 resistors are connected to same voltage, they are in parallel.
    This should help you understand summing amplifiers - http://www.ecircuitcenter.com/circuits/opsum/opsum.htm [Broken]
    Last edited by a moderator: May 5, 2017
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