Re: Inductance of a conical coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 >
 > Original poster: "Barton B. Anderson by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <classictesla-at-netzero-dot-com>
 >
 > At what frequency does the coil resonate at? I'm not sure how a flat
 > primary distributes current at low vs. high frequency's (the calc's are low
 > freq inductance's). I don't know how much has been studied in the primary
 > arena for the typical geometry's we use. Considering the low inductance's,
 > it may not take much to make a significant change, but possibly the
 > external cap may make for an even distribution.

The distributed capacitance of that coil is probably below 10 pF, but
really, in my measurement I was not very careful in avoiding parasitic
capacitances. About 150 pF would be necessary to explain the measured
resonance with a 5.08 nF capacitor at 287.9 kHz, considering the
calculated inductance (58.4 uH). Seems too much. I will make a better
measurement.

Antonio Carlos M. de Queiroz