Bubba Oscilator

Discussion in 'The Projects Forum' started by Chacabucogod, Oct 29, 2014.

  1. Chacabucogod

    Thread Starter New Member

    Nov 16, 2013
    26
    1
    I'm tryng to build a Bubba Oscilator with TL082 Opamps, but can't get it to oscillate in the simulation. I've added an initial charge to one of the capacitors, and yet it still won't work. I've looked on the forums, but there doesn't seem to be a clear answer as to why it wouldn't oscillate. Thank you.

    [​IMG]
    [​IMG]
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,009
    3,233
    Try increasing R24 to 3meg ohm or greater. The loop gain seems to be a little low for good oscillation.
     
  3. Chacabucogod

    Thread Starter New Member

    Nov 16, 2013
    26
    1
    Didn't Change anything :(
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Last edited: Oct 29, 2014
  5. crutschow

    Expert

    Mar 14, 2008
    13,009
    3,233
    My LTspice simulation of the circuit (which I think is essentially the same as yours) oscillates as shown below. I used the .ic command to initially set the voltage at one of the nodes to help start the oscillation.
    I added two back-to-back zeners as a clipper to limit the voltage since the generic op amp model has no inherent voltage limit and the amplitude would keep increasing indefinitely otherwise.

    Bubba Osc.gif
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,648
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    Cosine output taken from the wrong point?
     
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