Thanks for replying to my questions on grounding in Tesal coils Richard (btw
I have been trying to contact you at your email address for the past week but
have had no luck- I have just tried again so hopefully you will be receiving
a letter from me). There's still a couple of things that I'm not sure of:
OK, your resonate coil is generating a very large voltage at the
top of the coil, the location of the 1/4 wave voltage peak. There
is not a whole lot of current at the 1/4 wave location both in
theory and in practice.
The base of the coil however is a "nul" voltage point, or ground
potential. There is not a whole lot of voltage here, but the RF
current is plentiful and heavy, both in theory and in practice.
The ability of the coil to process power requires that the current
at the base wire be removed as quickly and efficiently as possible.
If this current is not removed and a high impedance ground path
exists, then the coils ability to produce very high voltage is limited.
I think I understand what you are saying - a Tesla coil acts as a
transmission line, the length of the wire in the secondary is such that the
voltage wave induced in it from the primary is max at the top of the coil and
min at the bottom of the coil. Similarly the induced current wave is the
other way around-max at the bottom and min at the top.
What I still dont get is why current must be removed quickly from the bottom
of the coil- does having a high current here somehow impede the induced
voltage. Is it like an inductor where the current flowing in the inductor
sets up a magnetic field which opposes any changes in the voltage across the
Hold it - I've just had a brainwave. Does the current flowing in the
secondary produce a magnetic field which acts back on the primary and tries
to reduce the current flowing in the primary by creating an opposing current
in the primary? - No on second thoughts that wont work , in normal
transformers increasing the secondary current results in more current flowing
in the primary (energy conservation).
As you can see from the above I am hopelessly confused. I have a fair
understanding of low frequency non-rf electricity but rf stuff bamboozles me.
Any help would be most appreciated.
_/_/_/ _/_/_/_/ Mark Conway
_/ _/ _/ Deep Thought BBS, Auckland, New Zealand
_/ _/ _/ A FirstClass(tm) Macintosh GUI BBS
_/_/_/ _/ Internet: mconway-at-deepthnk.kiwi.gen.nz