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VK200 r.f choke maximum current

Discussion in 'General Electronics Discussion' started by tzitzikas, May 20, 2010.

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  1. tzitzikas

    tzitzikas

    16
    0
    May 9, 2010
    i have a linear amplifier which is using VK200 r.f choke (at input voltage). I would like to ask you which is the maximum current? Because when i operate the linear (7A current) the VK200 r.f choke is very very warm. thank you
     
  2. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    I'm not suprised it gets hot !! doing some research on that choke tells me its a small 6 hole ferrite bead with relatively fine wire through it ~ 25 SWG its good for an amp or 2
    maybe 3amps at the extreme. You need a considerably larger ferrite core and much heavier gauge wire for a ~7A current.

    an example .... look at the chokes on the high current +5 and +12V outputs on a
    computer PSU board. Rat one off a dead PSU ... if its an HF transmitter amplifier ... one of those chokes would probably do the trick. For VHF or UHF a few less turns through
    the ferritr core

    Dave
    VK2TDN
     
  3. tzitzikas

    tzitzikas

    16
    0
    May 9, 2010
    hi. i am thinking to replace the vk200 choke with some turns of wire, on ferrite bead.
    i have some pieces of this ferrite bead: FB-43-7351 from amidon (43 material)
    look here: https://www.amidoncorp.com/items/44
    how many turns i must use to have the same inductance with the vk200. i don't know how to calculate the number of turns, and also i don't know the vk200's inductance.
    (the circuit is an mw band (600-1800khz) linear amplifier),
    and the maximum current is 15A.

    If i use 4 vk200 (in parallel ) i will use the same inductance or 1/4 inductance, It will work?
     
    Last edited: May 21, 2010
  4. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    they dont look as tho you can get a thick wire through them let alone a number of turns

    look again at the suggestion in my first posting those chokes have the current handling
    capability you need, as well as the sort of inductances needed at Low HF freqs.
    the other things you are wanting to try DONT have the current capabilities forget them


    Dave
     
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