Re: resistance of tank circuit

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Daniel,

The "power factor" is normally the SIN of the angular difference 
between the voltage and current sine waves in a steady state 
system.  A Tesla coil is not very steady state at all so the power 
factor varies over time and may lack any real meaning.

Pure inductors and capacitors have very low power factors since the 
voltage and current waveforms are out of phase by 90 degrees (SIN(90) = 0).

The "reactance" might be what you are looking for and that can be 
calculated from the equations on page 1 here:

http://hot-streamer.com/temp/FormulasForTeslaCoils.pdf

At resonance, the reactance of the capacitor and inductor will be the same.

You might also refer to "surge impedance" on page 6.  Surge impedance 
is sort of a measure of resistance of the primary circuit as a 
whole.  That is often used for things.

There is a similar thing here but for dynamic output impedance:

http://hot-streamer.com/TeslaCoils/Misc/impedance/impedance.html

I think programs like Bart's JAVA program calculate these numbers too 
but the equations are pretty easy to use directly.

Spark gaps typically have an "average resistance" in the 2 to 4 ohm 
range.  That is measured by checking the ring down time of the bare 
primary system to determine the series resistance.

Maybe this helps, or maybe you could be more specific if not.

Cheers,

        Terry




At 10:13 PM 4/30/2006, you wrote:
> Hello, I am interested in finding the power factor and phase angle 
> of my voltage and current waveforms for my primary coil and tank 
> cap.  What is the best way to do this?
> The inductor has a reactance of 51.7 ohms at 144kHz, and the 
> capacitor has a reactance of 51.5 ohms at 144kHz.  How do i find the 
> resistance of my capacitor, inductor, and spark gap? (no multimeter)
>
> Thanks for the help
>
> Daniel
>
> _