Variable frequency AC sources?

Discussion in 'General Electronics Chat' started by electronice123, Feb 1, 2014.

  1. electronice123

    Thread Starter Senior Member

    Oct 10, 2008
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    Hi everyone,

    I am in need of a variable frequency AC power supply. The only problem, do they exist? I need something than can go from the low Hz to about 8kHz.

    I know there are Variable frequency drives, but they are expensive and don't go into the kHz range.

    What ways could variable AC frequency be achieved?
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    You need to be far more specific in terms of your requirements.
     
  3. electronice123

    Thread Starter Senior Member

    Oct 10, 2008
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    I need a power supply that will give me variable frequency AC from 100Hz-8kHz. I need the output power to be at least 60VA.

    I just want to know if such a device exists which could do that? Or if I should look into other options.
     
  4. wayneh

    Expert

    Sep 9, 2010
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    Use an iPod and a frequency generator app. It can easily give the frequency range you cited, with enough power to drive headphones. If you need more juice, plug the iPod into your home theater or your guitar amp or your car stereo.

    [oops] Yes, you'll need an amp.
     
  5. redplaya

    Member

    Jan 26, 2014
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    build your own inverter yo
     
  6. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Was that 60 VA @ Maximum load current of ??? Amps? That's why I said you need to be specific about your requirements.
     
  7. crutschow

    Expert

    Mar 14, 2008
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    60VA could be generated by an oscillator to the input of a high power audio power amplifier, depending upon the load you want to drive.
     
  8. electronice123

    Thread Starter Senior Member

    Oct 10, 2008
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    Sorry, 30V @ 2A.
     
  9. electronice123

    Thread Starter Senior Member

    Oct 10, 2008
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    Ok, now that makes sense. I never thought of that. Exactly what I was looking for.

    I was thinking I would have to have a motor generator or something like that....What you suggested is a great idea. Thank you!
     
  10. wayneh

    Expert

    Sep 9, 2010
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    Exactly what I suggested in #4. I guess I wasn't clear.
     
  11. ScottWang

    Moderator

    Aug 23, 2012
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    ....Vin → NPN Bjt → Vout
    ...NE555..LC_↑ (F-adj)

    ....Vin → N type Mosfet → Vout
    ...NE555..LC___↑ (F-adj)
     
    Last edited: Feb 1, 2014
  12. crutschow

    Expert

    Mar 14, 2008
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    So you will need an audio amp that's rated for at least 65W into 16Ω, or 115W into 8Ω continuous power to get 2A @ 30V.
     
  13. MrChips

    Moderator

    Oct 2, 2009
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  14. electronice123

    Thread Starter Senior Member

    Oct 10, 2008
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    Thanks for the ideas everyone.
    For some reason I never thought of using an audio amp.
    Anyways, should make a great benchtop variable frequency ac power supply for all kinds of experiments.
     
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