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Re: Characterizing my Secondary

Original poster: "Bart B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Mike,

Measure the coil about 20" off the ground vertically. Drive the base. The coil if wound at 1400 turns should resonate at about 143 kHz. If you still are measuring 204 KHz, then you must have closer to 1000 turns.

Take care,
Bart

Tesla list wrote:

Original poster: "Mike Knowlton" <amdx@xxxxxxxxxxx>

 Hi All,

I'm probably jumping ahead a little but I'm curious.

 My coil is wound on an 8-1/2' by 42' plastic tube.
I wound and varnished an 8-1/2" by 39-7/8" coil on the tube.
I figure about 1400 turns of #22 wire.
I hung the coil horizontally 3 ft off the floor.
I lightly coupled a signal generator to the coil.
( I had the Gen. wires a few inches from the coil)
I put the 10x osc. probe near the coil to pickup the signal.
I found a self resonance at 204,620 Hz.
The Q was about 225.

I then connected a 100 pf. polystyrene cap. across the coil and
found a resonance at 54,081Hz with a Q of 232.
 Using the formula;
L = 1 / (4pi^2 f^2 c)
I get 87mh for the inductance of the coil.

Does all seem about right?

                  Mike

P.S. When I connected the 10x probe (15pf. 11meg.) across the
coil it resonated at 95,860 Hz. Q= 100