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Re: Ultra tiny coils!



Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Bart,

Thanks for the correct analysis!!

20MHz is still high for poly caps, but if it works it works I guess! Looks like all it really takes then is some 40ga wire and a 250pF cap!

Cheers,

        Terry

At 10:41 PM 2/8/2005, you wrote:
600 MHz!?
150 MHz?

Far too high. If this is the little 5x20mm coil, I'm getting about 20 MHz on the sec and 21 MHz on the pri. Only 5.8% detune which is normal. I noted the sec turns can't be correct (schematic showed 550T and coil page showed 350T). However, .07mm wire must be less than 300T for a 20mm length (without overlapping). I used 285T for calcs (should measure 20 ohms with DC meter or should count 142T per cm). It was interesting to note that when the turns were brought in to what I figure is closer to reality, both circuits were well in tune. The meter used is probably having difficulty with the measurements and this may be better modeled in a capable program.

Accuracy is uncertain, but due to the "tuned" results, it's close.

Courtesy of JAVATC.
The results below for anyone interested with specifics.

Take care,
Bart B.


ALL inputs are cm. ---------------------------------------------------- J A V A T C v.10 - CONSOLIDATED OUTPUT Tuesday, February 08, 2005 9:20:40 PM

Units = Centimeters
----------------------------------------------------
Surrounding Inputs:
261.62 = Ground Plane Radius
261.62 = Wall Radius
381 = Wall Height
261.62 = Ceiling Radius
381 = Ceiling Height
----------------------------------------------------
Secondary Coil Inputs:
Current Profile = G.PROFILE_LOADED
0.25 = Radius 1
0.25 = Radius 2
1 = Height 1 (1cm above groundplane)
3 = Height 2 (2cm + 1cm above groundplane)
285 = Turns
0.007 = Wire Diameter (cm)
----------------------------------------------------
Primary Coil Inputs:
0.35 = Radius 1
0.95 = Radius 2
1 = Height 1 (1cm above groundplane)
1 = Height 2 (1cm above groundplane)
4 = Turns
0.09 = Wire Diameter (cm)
0.00025 = Primary Cap (uF)
----------------------------------------------------
Top Load Object Inputs (dimensions & topload or ground connection):
Toroid #1: minor=0.45, major=1.3, height=3.3, topload
----------------------------------------------------
Secondary Outputs:
20144.81 [kHz] = Secondary Resonant Frequency
90 [deg°] = Angle of Secondary
2 [cm] = Length of Winding
142.5 = Turns Per cm
0.00018 [cm] = Space Between Turns (edge to edge)
39 [awg] = Recommended Wire Size
4.48 [meters] = Length of Wire
4 = H/D Aspect Ratio
20.06 [ohms] = DC Resistance
10778 [ohms] = Reactance at Resonance
10981 [ohms] = Forward Transfer Impedance
0.085 [mH] = Les-Effective Series Inductance
0.082 [mH] = Lee-Equivalent Energy Inductance
0.09 [mH] = Ldc-Low Frequency Inductance
0.733 [pF] = Ces-Effective Shunt Capacitance
0.68 [pF] = Cee-Equivalent Energy Capacitance
1.257 [pF] = Cdc-Low Frequency Capacitance
0.015 [mm] = Skin Depth
0.511 [pF] = Topload Effective Capacitance
----------------------------------------------------
Primary Outputs:
21385.64 [kHz] = Primary Resonant Frequency
5.8 [%] = Percent Detuned
0 [deg°] = Angle of Primary
16.34 [cm] = Length of Wire
0.06 [cm] = Average spacing between turns (edge to edge)
0.1 [cm] = Primary to Secondary Clearance
0.222 [uH] = Ldc-Low Frequency Inductance
0.653 [uH] = Lm-Mutual Inductance
0.147 [k] = Coupling Coefficient
6.8 = Number of half cycles for energy transfer at K
0.16 [uS] = Time for total energy transfer (ideal quench time)

----------------------------------------------------
..................