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Re: frequency (fwd)
Brent
What about solid state/tube coils? they use no spark gap - the high power
oscillator drives the primary tank at the right frequency. I would only say
that
the spark gap helps to stop HF energy from the secondary from being
absorbed in the
primary tank when the gap quenches. This is why tube coils are so much less
efficient - the primary tank is never 'open circuit' and thus energy will be
dissipated both in primary and secondary circuits. If we could find a
better way to
'bang' the primary and shut off all that huge current flow (and withstand
kickbacks) within a few uS with tubes or solid state switches (maybe next
century!)
then we could do away with our SGs. For the time though, the SG is the most
robust
and fast, and *noisy* switch we can find....
Alex
Tesla List wrote:
> Original Poster: Brent L Caldwell <stretchmonster-at-juno-dot-com>
>
> Original Poster: Brent Caldwell <StretchMonster-at-juno-dot-com>
>
> Marius:
> Earlier you wrote about whether or not it is okay to skip the
spark gap
> if you have a current source of the right frequency.
> The answer to your question is no. Creating a current source of the
> right frequence to resonate with the secondary is the job of the primary
> coil and capacitor. The transformer's job is to supply power to the
> capacitor. The spark gap performs a special function in the tesla coil
> tank circuit.
> The secondary coil produces its high voltage whenever the
magnetic field
> through it changes. The faster the magnetic field changes, the more
> voltage. Note, that contrary to popular misconception, a steady magnetic
> field through a coil of wire will not induce a voltage. Only a CHANGING
> magnetic field through the coil will induce a voltage. The changing
> magnetic field is provided by the primary coil. In order for the primary
> to produce a rapidly changing magnetic field, it must have a sudden rush
> of current through it.
> The spark gap's job in all this is to help provide that sudden
rush of
> current. As the capacitor charges from the AC source, the voltage across
> the spark gap increases. Eventually, the voltage across the spark gap is
> so much that it arcs. When it arcs, all of the charge on the capacitor
> rushes through the primary coil. This rush of current through the
> primary coil creates a rush of magnetic field which creates a high
> voltage in the secondary as explained above.
>
> Brent.
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