Resonance Frequency!

Discussion in 'The Projects Forum' started by ThapeloCornelius, Sep 26, 2013.

  1. ThapeloCornelius

    Thread Starter New Member

    Sep 25, 2013
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    Hello,

    How can i create resonant frequency using LC circuit (parallel or in series) and using DC supply , and how can i measure for resonant frequency using oscilloscope?

    Thanks
     
  2. #12

    Expert

    Nov 30, 2010
    16,252
    6,749
    You can not make a circuit that resonates at zero frequency (DC).
    However, when you first connect the DC supply, the pair will respond with a short (time) oscillation. You can use an oscilloscope to look at the fluctuations and might be able to find the time interval. That will lead you to the resonant frequency.
     
  3. ThapeloCornelius

    Thread Starter New Member

    Sep 25, 2013
    7
    0
    Thanks.

    So you saying i can get a resonant frequency if i supply my circuit with AC?. If so, can i use the oscilloscope to see the signal?
     
  4. #12

    Expert

    Nov 30, 2010
    16,252
    6,749
    Yes, and yes.
    However, you will see the signal best if the AC you supply is the same frequency as the resonance.
     
  5. ThapeloCornelius

    Thread Starter New Member

    Sep 25, 2013
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    0
    Thank you for your time.

    The thing is I am doing a project which i have to use the IGBT for switching, so i wanted to create resonance so that the current in my LOAD will be AC but drawn from DC supply.
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    Work out the resonant freq from the formula if you know the inductance and capacitance,F=1/6.484x root LC
     
  7. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    A series or parallel resonant circuit is just that, a resonant circuit, whether any voltage AC or DC is applied or not.

    To determine the resonant frequency you either have to calculate it (if you know the inductance and capacitance values) or measure it by applying an exciting voltage, usually by applying a variable frequency signal to the circuit, and using an o'scope or RF voltmeter as an indicator.

    In the olden days we used a grid dip meter to determine resonant frequency. A GDO is simply a variable frequency oscillator with a meter that will indicate a 'dip' when the oscillator is tuned through the resonant frequency
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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  9. Ramussons

    Active Member

    May 3, 2013
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    Are you on to Induction Heating? The technique used is different.

    Ramesh
     
  10. w2aew

    Member

    Jan 3, 2012
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    adam555 likes this.
  11. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    In general, resonance occurs when capacitive reactance equals inductive reactance.
     
  12. ThapeloCornelius

    Thread Starter New Member

    Sep 25, 2013
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    0
    @Ramesh, Yes Im on induction heating, can you help with the technique used?
     
  13. Ramussons

    Active Member

    May 3, 2013
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    92
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