Considerations when building a HV RF transformer?

Discussion in 'The Projects Forum' started by electronice123, Jun 19, 2009.

  1. electronice123

    Thread Starter AAC Fanatic!

    Oct 10, 2008
    I want to build a transformer which will be driven with a square wave and provide an output voltage of 10-20kV at the lowest current possible.

    The transformer's secondary coil will be like that of an ignition coil where one side of the secondary is grounded with the primary coil.

    The transformer will use a ferrite core and operate in the RF range.

    What factors need to be taken into account when building a transformer of this type???

    What kind of resistance would I need in the secondary winding to limit current as much as possible when operating at 10-20kV?

    How can I make the transformer have a high leakage inductance to limit current?

    It seems to me like there's a lot I don't know about building a transformer, and using high voltages I might just be better off buying one. Where can I get a 20kV transformer that can operate in the RF range?
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Last edited: Jun 19, 2009
  3. gerty

    AAC Fanatic!

    Aug 30, 2007
    you might consider using a flyback transformer, there are plenty of circuits on the web for driving one. But, as has been mentioned before, it helps to pick a range
  4. electronice123

    Thread Starter AAC Fanatic!

    Oct 10, 2008
    Yeah I forgot to mention the frequency. The range will probably be around 10-50kHz.

    I have been told by others that a flyback would work well. One question I have on flybacks, can the primary be connected in reverse polarity to get a HV negative output?

    From what i have read flybacks operate at 15kHz.

    Where can I get some flybacks at a good price?
  5. electronice123

    Thread Starter AAC Fanatic!

    Oct 10, 2008
    OK, sounds good.

    The frequency range will be 10-20kHz.

    I have a few questions about flybacks though, how high of a frequency can they go without alot of losses?

    Can I also get a negative High voltage by reversing the polarity of the primary?

    How can I make the flyback safe from it's capacitive charge?