# Re: Tuning Questions

```Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ben,

It is a great question!!  Nothing is more fundamental to getting a Tesla
coil to work as is tuning.

The primary and secondary circuits of a Tesla coil must be tuned to the
same frequency for the thing to work.  The primary and secondary circuit
are basically a capacitor and an inductor joined together that will
oscillate at a frequency of:

F = 1 / (2 x pi x SQRT (L x C))

F = Frequency in Hz
pi = 3.14159265...
SQRT = The square root function
L = The inductance of the coil in Henrys
C = The capacitance of the capacitor in Farads

So when the spark gap closes, the primary circuit will oscillate at say
150kHz and the secondary (also tuned to 150 kHz) will pick up the magnetic
signal and convert it to cool sparks.  there is a ton of great information at:

So, how "does" one tune the Tesla coil.  There are three ways:

1.  Wire the thing up and hope it works. :-))  In the "good old" days, we
all used this method.  Mine never worked but a few people got lucky...  You
just build the coil and tap the secondary at different places and hope that
big streamers shoot off the top.  The big problem is that if it does not
work, it is going to be messy fixing it.  This method is far more
successful if you directly copy someone else's coil that works good :-))
Another fix is to write us here on the list telling that your new coil only
has 1 inch sparks and we will asked a bunch of questions and figure it all
out for you :-))

2.  Buy a whole bunch of test equipment and measure the primary and
secondary frequencies of oscillation and adjust things just right.  This
works great but requires a fair knowledge of electronic testing and a boat
load of money or time searching the Earth for bargain test equipment.  One
low cost tool that may help a bunch is my tesla coil tuner:

http://hot-streamer-dot-com/TeslaCoils/Misc/TCT/TCT.htm

It still needs a little electronic knowledge but it can handle many tuning
problems for not too much money.

If your have money to burn, here are my toys before I spent another \$6000
on even more :-))

http://hot-streamer-dot-com/TeslaCoils/Misc/PaulNich/TheToys.jpg

3.  Computer programs.  Recently, computer Tesla coil programs have gotten
super good and they can do all the work for you.  If one is careful, you
can now make a Tesla coil from scratch that will be tuned just right from
the start with today's programs.  All the main programs are super good:

There are also other programs too but this is the link I had handy.  I
should probably start a programs link page of my own...

Cheers,

Terry

At 03:48 PM 5/22/2001 -0500, you wrote:
>
>This is a completly ignorant question :) but how do you tune yor
>coil?
>
>                    Ben
>

```