Op Amp Output Ripple

Discussion in 'General Electronics Chat' started by ion beam nerd, Jan 27, 2015.

  1. ion beam nerd

    Thread Starter New Member

    Jan 26, 2015
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    Dear All,
    I've built a simple op amp summing amplifier using an LM358 (see attached). The circuit is used to control the electrostatic scanning plates for a charged particle beam. A saw-tooth function (1 kHz) is applied to one of the summing inputs and a DC offset is applied to the other. However, the output from the op amp has a "ripple" artifact (see attached photo's). Has anyone ever seen this before, or see anything blatantly wrong with the circuit? (I'm a physicist, not an electronic engineer, by training so please be kind!)

    Cheers
     
  2. pwdixon

    Member

    Oct 11, 2012
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    Can you try the same circuit but with a true dual power supply?
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    Please show the X and Y scale units and zero level of the oscilloscope.

    Did you forget to ground the two 10k resistors of the pseudo split supply in the circuit schematic as well as the actual circuit?
     
  4. Jony130

    AAC Fanatic!

    Feb 17, 2009
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  5. pwdixon

    Member

    Oct 11, 2012
    488
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    You say you aren't an electronics engineer, so did you copy this circuit from somewhere? Can we see the original?
     
  6. ion beam nerd

    Thread Starter New Member

    Jan 26, 2015
    2
    0
    Jony193, thank you very much, that's fixed the problem. Thanks all for your help.
     
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