transzorb(TVS) testing method

Discussion in 'General Electronics Chat' started by omar, Apr 28, 2009.

  1. omar

    Thread Starter Member

    Feb 19, 2008
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    0
    I was wondering if you guys can help me to test several TVS.
    My main issue is how to create waveform pulse.
    i am having trouble grasping the concept of the (10/1000 us) in regard to the waveform geration.
     
  2. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    The 10/1000 us waveform I am familiar with the for simulated lightning strikes for telecom certification. The times were for the rise/fall to 50% of the specified voltage.

    So, for a 1000V test, the signal, which rises exponentially, must get to 500V in 10us. The decay must reach 500V in 1000us. We were unsuccessful in making anything that did not either overpower the equipment to be tested or missed the wave shape entirely. We ended up buying equipment to perform the tests on-site before final certification.

    Here is an illustration of the waveform we needed.

    http://www.compwest.com/Products/MegaPulseImages/10x1000-1_C_Vdur.pdf
     
  3. omar

    Thread Starter Member

    Feb 19, 2008
    10
    0
    Thanks for the reply , if you don t mind could you please tell the equipment you are using to generate expential waveform.

    Thanks again
     
  4. omar

    Thread Starter Member

    Feb 19, 2008
    10
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    i might have to buy those equipment and do the testing onsite
     
  5. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
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    This was a few years back so I don't remember exactly what equipment we used. I'll contact the people I know that are still there to see if they can check... I'll get back to you after they get back to me.
     
  6. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
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  7. omar

    Thread Starter Member

    Feb 19, 2008
    10
    0
    thanks for your help,
    I found some other equipment but they are really expensive.
     
  8. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    The only other things I could think of is see if you could rent something from one of the big equipment rental places, if available. Or, go to a testing facility that does telecom testing and see if they can run some basic tests, although I doubt this will be inexpensive either.

    The test setups that we used to generate the voltage in house used a variac, variable transformer, to charge a bank of capacitors through a resistor and then a series resistor to limit current on discharge to the unit under test. I did not work well, i.e. the waveform was not very close to the one specified. That's why we bought other equipment.
     
  9. omar

    Thread Starter Member

    Feb 19, 2008
    10
    0
    Did you guys ever try to test the breakdown voltage of the TVS at the test currrent specified at manufacturer datasheet ?
     
  10. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    We only ran the tests that were indicated in the Telcordia GR 1089 and similar requirements that were necessary for our equipment as a whole. We did not attempt to test or verify the upper limits of the individual devices themselves.
     
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