Capacitance Math

Ok, so we know where to tap and how much capacitance we need but how do we choose what capacitors to buy? Well first of all you need to know what the peek voltage of your transformer and that is NOT the rated voltage on it as that is RMS voltage. To work it out just times the rated voltage by root 2.

6000v = 8485v Peek
10 000v = 14142v Peek
12 000v = 16970v Peek
15 000v = 21213v Peek

Now you MMC must accommodation for the peek voltage of your transformer. Now is the hard part. You need to find capacitors that if you add all of there voltages together, you get the same or higher than you peek voltage and they must have a total capacitance as close as the CAD program has told you. Any more capacitance and the circuit will be out of resonance. This is hard but here is a link to a online calculator that will work out the voltage and capacitance of your MMC. 

http://deepfriedneon.com/tesla_frame6.html

I am using 9 0.15uF 1250v caps all in series. If you type these in the calculator you will see that the total capacitance is near my needed 0.159uF and the voltage is not too high but still clears the peek voltage limit. Also you need to make sure that the caps total voltage does not go over 1.5 times that of the peek voltage or your circuit will have a voltage too high that can cause damage to the transformer.

I am using 9 of these caps -

http://www.ebay.co.uk/itm/1250V-0-15uF-POLYPROPOLENE-CAPACITOR-WITH-METAL-FILM-ROHS-COMPLIANT-NEW-/400337027811?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d35f242e3

If you are making a Tesla coil with the same ratings and speks as mine you can use these and the amount of them as I have already done the math for you when I was making my Tesla Coil.

Getting the right combinations of all these factors IS the hardest part of making a Tesla coil but when its done you will know you will have a good efficient Tesla.

Next: Safety then starting to build it!