Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>
Hi All,
I've just done some more measurements, this time with a square wave and
looking at the harmonics on that. This time it resonates at 200KHz (wave
superimposed on square wave). For this test I connected my sig gen to the
base of my TC using a 1K resistor, and put my scope probe on the resistor
to TC connection. I injected a square wave and there was a harmonic at
approx 200KHz. I then set the sig gen to sine and tuned up to 200KHz,
where sure enough there was a resonant area.
So now my TC has 3 resonant frequencies, which one is the one that most
people go by??
Thanks
Chris
----- Original Message -----
From: <mailto:chris1@xxxxxxxxxxxxxxxxxxx>Chris Rutherford
To: <mailto:tesla@xxxxxxxxxx>Tesla list
Sent: Saturday, June 25, 2005 6:34 PM
Subject: Secondary Resonance LC and Harmonics.
Hi All,
I've just wound my first secondary, and in my eagerness I ignored most
guidance and just wound as many turns as possible on a piece of 3.5' x 4"
tubing. It turned out to be approximately 2K turns (gulp).
I managed to get my hands on a nice stainless steel sphere, which sits
nicely on top. I was just 'playing' with my scope and signal generator,
when I discovered that when I set the sig gen to oscillate at 76KHz or
416KHz I don't need to connect it to the coil in order to show the signal
on my scope, I only need to touch the probe and the signal magically gets
on to the coil and scope! - I'm guessing that my coil and top sphere are
acting as a tuned LC tank circuit, with a resonant frequency of 76KHz and
a harmonic of 416KHz. Either side of these frequencies the signal drops off.
Does this make sense? Has anyone else experienced something like
this? How *badly* tuned is my coil? Should I take some turns off it (not
yet varnished)?
Thanks
Chris