Connect with us

gain amplifier

Discussion in 'General Electronics Discussion' started by aletropot, Oct 16, 2015.

Scroll to continue with content
  1. aletropot

    aletropot

    15
    0
    May 12, 2013
    Hi all,

    I need to duplicate the voltage of a pwm. when 0.1v should out 0.2v; 0.4v - 0.8v; 1v - 2v; etc...
    Im using a non inverting op amp with a pot for adjustment, but it doesnt work like it should.
    Like, when is 0.2v the out is 0.3v and when 1v is 2.4v.
    I've tried with tl071 and lm324 and they behave differently, but both not correctly.
    Any tips?
     
  2. LvW

    LvW

    604
    145
    Apr 12, 2014
    Yes - my first tip: Show us the circuit.
    If a circuit does not work - nobody can find the reason without knowing how it looks like.
     
    Arouse1973 and Martaine2005 like this.
  3. aletropot

    aletropot

    15
    0
    May 12, 2013
    here
     

    Attached Files:

  4. Bluejets

    Bluejets

    3,645
    736
    Oct 5, 2014
    You need to supply the chip with power.
     
  5. aletropot

    aletropot

    15
    0
    May 12, 2013
    that obvious...
    its powered with 12v dc
     
  6. duke37

    duke37

    5,271
    730
    Jan 9, 2011
    Do the amps need a plus and minus power supply?

    The gain will depend on the potentiometer setting.
     
  7. GPG

    GPG

    452
    66
    Sep 18, 2015
    Needs to be a rail to rail input/output amp
     
  8. aletropot

    aletropot

    15
    0
    May 12, 2013
    The LM324N isn't one of these?
     
  9. duke37

    duke37

    5,271
    730
    Jan 9, 2011
    You can determine this if you look up the data.
    Thats obvious.
    The TL071 needs a plus and minus supply.
     
  10. aletropot

    aletropot

    15
    0
    May 12, 2013
    Im asking because have checked on the datashet.
    Plus on suggested applications the minus supply its connected to ground on all examples.
     
  11. BobK

    BobK

    7,664
    1,678
    Jan 5, 2010
    For a gain of 2 you need equal resistor for feedback and to ground. An LM324 should work okay as long as the supply is 2V greater than the max output you need. Here is a simulation. Note that below about 100mV the output will not be accurate because the op amp cannot output all the way down to 0V. If you need accuracy in that region, you will need a dual supply.

    upload_2015-10-17_15-39-1.png

    Bob
     

    Attached Files:

  12. aletropot

    aletropot

    15
    0
    May 12, 2013
    It is, but I need accuracy on lower values, so to simplify I'll use a dual ps.
    thanks all
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-