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Experimental Design For Measuring Dielectric Breakdown of Gasses

  1. Feb 23, 2012 #1
    Hi, I am an undergrad working on designing and carrying out an experiment for a physics laboratory class. I've got the idea of measuring the dielectric breakdown of multiple gasses at differing pressures, however I've come to realize that there are going to be a lot of obstacles to overcome. Any advice that anyone could offer would be greatly appreciated.

    First off here's my concept for carrying out the experiment thus far: A simple circuit is set up with with voltage source and capacitor plates. The voltage is increased until arcing is visible or a large jump in current is measured, and the electric field across capacitor plates is calculated. The space between capacitor plates is a vacuum chamber that can be filled with gasses at different pressures, though obviously to be experimentally feasible this distance ought to be very small (somewhere between 1cm and 1mm). The voltage source needs to be quite high, though the best voltage source my school has currently produces only 3000V.

    So I have a few specific questions, please let me know if you could answer any of them.

    1. Is this experiment feasible? I only will have a budget of $100-200 to make any purchases. Though I should have all the gasses already at school that might be needed.

    2. Are there any safety concerns due to high voltage, or by-products produced due to electrical arcing?

    3. How might I go about purchasing or designing a vacuum chamber that can be set up to a pump and have pressures measured?

    4. For measuring breakdown of air, how would I dehumidify the air before putting it in the chamber?

    5. Once the breakdown voltage is reached, I need to find some way of limiting current, hopefully something more elegant than burning fuses. Any suggestions?

    6. Are there any geometric considerations for the plate capacitors I need to worry about?

    Thanks for the help!
  2. jcsd
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