Need help to solve this op amp

Discussion in 'Homework Help' started by horrormyth, Apr 28, 2012.

  1. horrormyth

    Thread Starter New Member

    Apr 28, 2012
    Hi Everybody,
    I'm just new to electronics
    Need a little help from you guys to solve this opamp,from where to start....
    Need very step by step ...and thorough help

    If vin =30 mv find vout

    Would be great...
  2. blah2222

    Well-Known Member

    May 3, 2010
    To start, you can assume that this is an ideal op-amp operating in the negative feedback mode and make two assumptions:

    1) V+ = V- and
    2) I+ = I- = 0

    What these means is that there is no current entering the input terminals of the op-amp and that both of the input voltages with be equal.

    Since V+ is tied to ground, V- will therefore be equal to ground using this model. KCL can be used to establish equations in terms of Vin, V-, and Vout and you will be able to solve Vout as a function solely of Vin.

    Hope that helped.
  3. panic mode

    Senior Member

    Oct 10, 2011
    start with opamp assumptions. ideal opamp has:
    1. inputs of high (infinite) impedance (input current is zero)
    2. inputs are at same voltage (opamp never saturates)
    3. output impedance is zero (output can sink or source any current)

    using those, you can write KVL and KCL for entire circuit. that's pretty much it.