Recent content by BertHickman

  1. BertHickman

    Electrons in a dielectric

    Yes. A pointed electrode can be melted into a transparent polymer, such as acrylic (polymethylmethacrylate), epoxy, or polycarbonate and a flat electrode applied to the opposite side of the polymer. When the pointed electrode is energized from a HV AC source or from a pulsed HV source, charges...
  2. BertHickman

    Why is dielectric breakdown damaging?

    Dielectric breakdown is not always damaging. For example, when it occurs in gases and many liquid dielectrics, the dielectric can recover all (or most) of its previous insulating capability once the arc or spark is extinguished. In gases, the conductive plasma channel taken by the discharge...
  3. BertHickman

    Dielectric breakdown

    As Physguy indicated, dielectric breakdown is primarily a function of the applied electrical field versus the dielectric strength of the oil, and is virtually independent of electrode resistivity for good electrical conductors (such as metals, alloys, and carbon/graphite). However, once...
  4. BertHickman

    Why does an Electromagnet Vibrate ?

    An electromagnet will behave the same as a magnet only when you power the electromagnet from a true DC source, such as a battery. If it is powered from a simple home-made DC power supply, then you're apparently getting some "ripple" current into the electromagnet - a portion of the AC waveform...
  5. BertHickman

    Voltage Breakdown over two parallel rods

    You might be able to do 2 cm. Make your ladder adjustable and lock it at the point where you get the best results. Because the circuit you referenced is low power, you may not be able to generate much heat in the arc, so you might not be able to separate the rods very much at the top...
  6. BertHickman

    Voltage Breakdown over two parallel rods

    Hi, You want to make sure that the gap at the bottom of the ladder will spark over so that the arc can start. Unfortunately, the above analysis has a math error that makes it off by a factor of 10. The DC breakdown voltage for a 1 cm sphere gap is actually closer to 30 kV (actually an...
  7. BertHickman

    Energy Stored leading to Dielectric breakdown

    That's the correct approach. The energy scales as the E-field squared, so quadrupling the energy doubles the required E-field, so the gas dielectric must be able to withstand a field of 6 kV/mm without breaking down.
  8. BertHickman

    Resonating Coils

    Making a coil that self-resonates at 7 Hz would require a coil of truly Herculean proportions - NOT practical. There are a number of Tesla Coil design tools that can estimate the self-resonant frequency of a secondary coil. An easy to use, and accurate, program is Bart Anderson's on-line JavaTC...
  9. BertHickman

    Resonating Coils

    That's not an odd question at all. It turns out that ALL coils will resonate at some frequency. That's because there is always some capacitance between turns and also stray capacitance to ground. The combination of these capacitances and the inductance of the coil form an LC circuit which will...
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