Integrator circuit values

Discussion in 'General Electronics Chat' started by pep, May 11, 2009.

  1. pep

    Thread Starter Member

    Apr 20, 2009
    Hello everyone,

    I'm designing a simple integrator circuit using PSpice 9.1 and an uA741 opamp.

    This circuit should be able to work in ms range (it is to be incorporated in more complex time delay feedback circuit). I realise that it is not a difficult design to built up; however I'm finding great troubles in to set R and C values in order to get the best integral possible (I have tried many values considering output values and I keep getting awkward shapes).

    Could someone help me in to set R and C values? What is the main procedure/calculations to follow?

    I would much appreciate any help in form of advice or good and reliable sources to look at.

    Thanks a lot buds,

  2. Audioguru


    Dec 20, 2007
    The lousy old 741 opamp is 41 years old. It has trouble with frequencies higher than only 9kHz. Most other opamps cost the same and respond well up to 100kHz.
  3. DonQ

    Active Member

    May 6, 2009
    Remember this. Farad = one volt per second per amp.

    That means if you put one amp into a one farad capacitor for one second, the voltage on it will change by one volt. You have to adjust for mV, μF and kΩ, but the equation is the same.

    You should be able to use this and ohms law to find the values you want.
  4. pep

    Thread Starter Member

    Apr 20, 2009
    Ok, thank you both for your good advice.

    Audioguru, could you let me know a few opamps that would work just fine for this application? I am using Pspice 9.2 to simulate the design, there are lots of opamps available but unfortunately I am lost in too much information.

    DonQ, thanks for your precise indication, I will follow it.