Variable capacitor application.

Discussion in 'Wireless & RF Design' started by PackratKing, Oct 8, 2015.

  1. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
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    215
    Greetings Ladies and Gentlemen...
    I am stepping off my normal turf here, with a question about a purely radio part.

    I am in the process of selecting components to put together a small RF induction heater, according to the attached schematic...
    [edit] I see I had my control element functions reversed. live / learn... Onward and Upward !!

    Lastly... how much RFI / QRM is this beast going to generate ??
     
    Last edited: Oct 9, 2015
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    That capacitor is 1000 times too low in value... You know, pF vs nF!
     
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  3. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
    850
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    I sort of figured that... If I had one of the proper range of capacitance would the idea fly ??

    See edit of post #1 still in the learning stage here, and " de-bugging "

    Thanks to one and all for advice and counsel...:D
     
    Last edited: Oct 9, 2015
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Biggest variable I have seen is about 1000pF
     
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  5. k7elp60

    Senior Member

    Nov 4, 2008
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    I think you should increase the size of the inductance. My calculations show your resonate frequency @212 khz. The inductor if I read correctly is 1.5uh. That is pretty small. What are the specifications for the diameter of the coil? It would be easier to increase the inductance and then capacitors in parallel would easily resonate the circuit. Heck I have built resonate circuits in the 3khz range.
     
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  6. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
    850
    215
    Thanks [ all ] for advice and counsel... I'm seeing that the variable idea won't fly, so will pursue the switching between fixed inductance... At that rate, I will be flying by seat-of-pants, winding assorted toroids with random heavy wire, as I've seen in other peoples' projects of this nature. [ I cannot afford an LCR meter yet ]

    Things will likely progress into more complex uses for the instrument, for now the only intended purpose is for a heat-source for silver-brazing a carbide cutter onto a random HSS. lathe tool, because I literally SUCK at torch-brazing.
     
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