Designing an amplifier circuit followed by a comparator

Discussion in 'The Projects Forum' started by Saswat Priyadarshi Nayak, Apr 15, 2016.

  1. Saswat Priyadarshi Nayak

    Thread Starter New Member

    Apr 15, 2016
    2
    0
    I have a signal output whose voltage ranges from 120uv to 15mv ...i need to set a reference point in between those voltages- (v) and V must be as closer to 120uv for minimizing error. the condition is i want to glow a led when voltage output is >V(ref voltage) and led in off state when voltage output < V.

    to do so i thought of amplifying the signal to range of volts and then use a comparator to make the led on and off for those ranges. But it seems that the ompamp i was using ic-741 had an offset voltage of 10mv.. due to which the voltage output from the amplifier circuit saturated to Vcc(sat).
     
  2. Saswat Priyadarshi Nayak

    Thread Starter New Member

    Apr 15, 2016
    2
    0
    My question is what kind of ompamp shall i use for this purpose ?? suggest me some.
     
  3. dannyf

    Well-Known Member

    Sep 13, 2015
    1,824
    364
    To go to what low of a level, you likely will need to create a negative rail - even R2R opamps aren't going to work at 120uv.

    I would use a dual opamp and one as amplifier and another as comparator.
     
Loading...