# Re: Static Spark Gap Design Questions

```Original poster: "D.C. Cox" <resonance@xxxxxxxxxxxx>

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A set of five pieces of 1/2 or 3/4 x 3.5 inch long parallel copper tubes (4 spark gaps) will provide better quenching action as the copper rapidly dissipates the heat and hence the heat sinks are not necessary.
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If you do elect to use the tungsten rods, start tuning with a total spark gap spacing of .060 inches (60 mils total max). After tuning, and finding your resonance point, then you can usually go up to 0.240 inches (240 mils) which allows your cap to charge to a higher value of energy before firing. At 30 mil charging current the tungsten will work ok, but you may give up some lost energy due to poor quenching if the edges of the rods begin heating to red hot. If you go this route you might consider a powerful 250 CFM blower across the spark gap.
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Heat sink separation of 1/4 inch should be adequate.

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The potential difference (voltage) at which the spark gap fires is nearly a linear function, however, the energy stored in the capacitor increases as the square of the potential across it, so the larger spark gap will provide much more energy into your primary circuit.
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Dr. Resonance

I'm in the process of designing and building a
static spark gap to be used with some table top
Tesla coil experiments that I plan to do.  I'll
be playing with various voltages and physical configurations.

The power source is a 12K 30 Ma NST controlled
via a variac and protected with a Terry
filter.  I'll be using a LTR mmc capacitor in the range of .015 MFD.

The gap proper will be made up of 10 ¼ inch
tungsten electrodes each mounted in a fined heat
sink and utilized to make 5 adjustable static
gaps which can then be connected in series or parallel configurations.

I'm thinking that I might like to develop gap
spacing for say 12 K, and then vary the number of
gaps used for 3K, 6K, and 9K, but that's one of many experiments planned.

I have a couple of questions for the list.
In my beginning design what would be a good maximum spacing for:
1.  The actual end to end of the tungsten rods?
2.  The side to side spacing between the heat sinks?

TNX

NT

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