Flyback Capacitor Charger Question

Discussion in 'The Projects Forum' started by airplane100000, Sep 20, 2016.

  1. airplane100000

    Thread Starter Member

    Aug 2, 2016
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    0
    Given the following example:
    A flyback converter charges a 10nF capacitor to 4kv. When a 100k load is attached to the charged cap it discharges in ~3ms. Now with the load attached, the cap no longer charges to 4kv, it instead delivers a more or less steady 500v to the load. Only when the load is disconnected will it charge again to 4kv.

    My question: Is there anyway to replicate the connecting and disconnecting of the 100k load without doing so physically. In other words, is there a way to allow the cap to charge to several kilovolts before discharging.

    Thanks for any help!
     
    Last edited: Sep 20, 2016
  2. crutschow

    Expert

    Mar 14, 2008
    13,050
    3,244
    I don't see you could not do it physically. :confused:
    You could use a hypothetical high voltage switch or relay to disconnect the resistor during charge.
     
  3. airplane100000

    Thread Starter Member

    Aug 2, 2016
    59
    0
    Could you use a varistor in series before the load, which would show high resistance when the cap is at a low voltage and lower resistance as it charges up? Or is that a foolish idea...
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,050
    3,244
    Likely nothing that would stand 4kV.
     
  5. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,964
    387
    You could use a PL504 (rated to 7kV) to switch it.
    Thermionics make a comeback.
     
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