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Eimac Type 8533 Planar Triode Connections?

  1. Sep 23, 2008 #1
    Hello All!

    Can anyone identify the filament, cathode, grid, and anode (plate) connections of a Eimac type 8533 planar triode tube? I need to maufacture a custom fixture/holder to power this tube and
    the connections are apparently to the actual metal/ceramic housing of the tube.

    I have the data sheet but it gives no connection info.

    Thanks very much!
    Last edited: Sep 23, 2008
  2. jcsd
  3. Sep 23, 2008 #2


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    How many pins are there? The filament should be obvious. Do you have access to tube-tester manuals? They may tell you. If it were me I would simply try some things using current limiting resistors so the tube is not damaged. Sooner or later it would make sense.
  4. Sep 24, 2008 #3
    Hello, and thanks for the quick reply!

    The problem is that there are no pins!

    The tube housing is metal and ceramic (no glass) and the connections are directly to the metal housing.

    I would guess the filament is easy, just look for 2 points with low resistance, but the anode, cathode and grid are stumping me.

    Best regards,
  5. Sep 24, 2008 #4
    What are you using the triode for?
  6. Sep 24, 2008 #5
    Hi, thanks for the reply.

    Im using the triode to switch high voltage (3kv), at 200 khz.

  7. Sep 24, 2008 #6
    How about IGBT devices or similar.? Not sure if they will manage that switching speed??

    http://www.dynexsemi.com/products/igbt/3300.htm [Broken]

    (Looking at the spec for one device they give input capacitance at 1 MHz.)

    E-mail Wilson Valves... He has sent me circuit diagrams for free.

    Last edited by a moderator: May 3, 2017
  8. Sep 24, 2008 #7
    I need a super fast rise and fall (< 10ns)...rules out most semiconductors.

    Sometimes old tech is still superior.
  9. Sep 24, 2008 #8
    There are still areas where valves rule and probably will continue to do.
  10. Sep 26, 2008 #9


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    It's been a long time since I did anything with this, but IIRC they just went in order.
    Filament filament cathode grid plate.
    The plate connection having the largest separation from the other contacts.

    Perhaps if you contacted the ARRL they might have some more info on the tube and socket availability.
  11. Sep 26, 2008 #10
    Thanks VERY much to all who helped!
    Problem solved.
    Cathode / Heater at bottom
    Grid at second ring
    Plate / Anode at top.
    I powered it up, It functions properly, and I'm still alive!
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