[Prev][Next][Index][Thread]
Re: Can I touch?
This is great feedback. I had no idea that disruptive type TCs would pack
such a wallop. Now I'm
beginning to think that I may want to build a smaller tube type TC similar
to the one I built in the 60's,
instead of an NST/spark gap based one. I really like the effect of
demonstrating to others that you can let the sparks fly to your fingers.
Any one have a schematic of a TC that uses readily available tubes -- like
audio power amp tubes (I used 6L6's in my original) or maybe old TV
horizontal drive tubes? (And I just traded a 100th tube off -- oh well.)
Another question: is there a way to make the disruptive spark gap type more
safe to the touch? Raise the frequency? Use a high speed rotary spark gap?
>
> Bill,
>
> Good.... While the output from low-power vacuum tube CW coils is
> probably harmless, larger-power tube coils can deliver sigificant output
> current, and the danger with this is two-fold. First, if you let the
> sparks directly hit your skin, the "entry points" are actually little
> burned puncture holes, the surrounding tissue is actually charred, and
> the smell of burning flesh can permeate the air. As long as you keep the
> sparks moving, little permanent damage will be done. Taking a sustained
> arc in one place will create a nasty, slow-healing RF burn. Secondly,
> letting the sparks hit a piece of metal in your hand will prevent the
> above external burns, but the RF current STILL tends to flow _through_
> your nervous system and blood vessels.
>
> "Skin effect" does NOT protect your body - at 100 kHz the skin depth of
> your body is about 39 inches! Make no mistake here - TC RF currents
> flow THROUGH your body, not on the surface or through your skin. Your
> skin, in fact, is a relatively poor conductor compared to your mervous
> system, blood vessels, and major organs. Compounding this, your body's
> pain sensors do NOT provide you with any warning that you may be
> slow-cooking your innards. And, the higher the coil's power, the more
> risky this behavior becomes. Symptoms of nerve or tissue damage include
> dull pain or aches in the muscles or joints (sometimes hours later), or
> tingling or numbness that (usually) goes away with time.
>
> Unlike a Tube Coil, a discharge from a disruptive (spark-gap) coil will
> almost always give you some sensation of electrical shock. This ranges
> from barely noticable in small coils to body-convulsing potentially
> _fatal_ jolts off larger systems. The higher peak power levels, combined
> with the typically large topload capacitance mean that higher peak
> output voltages are produced. And, when you take a hit off a
> medium-sized system, it's NOT an RF discharge. Instead, it's more like a
> HV capacitor discharge going through your body, and the peak current can
> easily be in the ampere range if the discharge arcs from you to ground!
> You don't want to be on the receiving end of 200-300 kV hit from a
> charged 30-50 uF topload/coil capacitance - at best it'll really rattle
> your teeth, and the resulting muscle contractions may cause further
> injury.
>
> If you still feel you must try this, keep your power levels low (close
> down your main spark-gap), stick will a small coil, stand on a well
> insulated platform so that you're NOT grounded, and have a trusted
> associate control power to the coil. Most experienced coilers avoid this
> practice...
>
> Safe coiling and happy holidays to you!
>
> -- Bert --
>
>