Variable frequency sine wave

Discussion in 'The Projects Forum' started by gagan, Sep 20, 2009.

  1. gagan

    Thread Starter New Member

    Sep 20, 2009
    2
    0
    hey guys. I want to build a variable frequency sine wave generator with a constant amplitude. any suggestions??

    Thanks,
    G
     
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    893
    A Wien Bridge oscillator using a light bulb or a Jfet for amplitude stabilization works well.
    Mine goes from 10Hz to 100kHz.
     
  3. gagan

    Thread Starter New Member

    Sep 20, 2009
    2
    0
    hey thanks for the quick reply

    I'm considering the following circuit
    http://www.national.com/ms/LB/LB-16.pdf
    Figure 1 Easily tuned sine wave oscillator

    Can any one help me by explaining what exactly how sine wave is being genrated in the circuit.

    Audioguru:- I did consider wien bridge option but can't figure out how to control the amplitude using jfet exactly. If you could explain a bit more on that part, then it will be great.

    Thanks
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,732
    2,467
    How pure does this sine wave have to be? If the answer is not extremely, then you can use other methods.

    [​IMG]

    To answer your question the Zeners clip the wave form, leaving what is effectively an active filter to clean up the harmonics.
     
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