New Transformerless Tesla Coil

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Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>


New Transformerless Tesla Coil

Today I finished preliminary trial of new transformerless mini-TC built
according to Antonio s calculations.

Specifications:-

Power supply: Flyback transformer (internal rectifier) driven by 555 astable
running off 13.8V 3A DC supply.

Capacitor: 255pF 

Sixteen platic film can saltwater-gel capacitors wired as

8 parallel strings each of 2 capacitors connected in series; the "gel" is
wallpaper paste to which salt has been added, sealed off with a layer of melted
beeswax.

Spark gap 3-4mm gap between wires.

L1: 61 uH

45 turns 24 SWG enamelled copper wire on 33mm diameter plastic film can former

winding length is1.122".

L2: 5.482mH 1004 turns of 40SWG ECW on 1 1/8" diameter vitamin pill tube former

winding length 5 5/16"

Topload: 2" diameter plastic disc, coated with metal foil.

So far I have got faint 1/2 inch sparks to grounded wire with copious corona
and ozone generation (are fine RF sparks and corona are better at producing
ozone than bright low-frequency or DC discharges?); the TC is easily capable of
lighting a 20 Watt fluorescent tube from a distance. 

Performance-wise, is this to be expected, only while it has been a bit -well
"miniature" so far, judging from the spark length there is apparently voltage
magnification and I am anticipating using the TC with bigger capacitors for
larger sparks. 

Could L1 be better designed -is the Q likely to be low? If I use larger
capacitor will a bigger topload bring it back into tune -or will it simply
become untuneable?

I would be interested to read of experience with transformerless TCs especially
with "mini"coils as I hope to build some easily portable designs capable of
producing big sparks when running off integral batteries so maximum "bang per
buck" would be an advantage.

And are transformerless TCs likely to be more common in future?