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*To*: tesla@xxxxxxxxxx*Subject*: Coiling myths*From*: "Tesla list" <tesla@xxxxxxxxxx>*Date*: Mon, 04 Apr 2005 12:55:16 -0600*Delivered-to*: testla@pupman.com*Delivered-to*: tesla@pupman.com*Old-return-path*: <teslalist@twfpowerelectronics.com>*Resent-date*: Mon, 4 Apr 2005 12:57:56 -0600 (MDT)*Resent-from*: tesla@xxxxxxxxxx*Resent-message-id*: <WjsySB.A.RXH.y4YUCB@poodle>*Resent-sender*: tesla-request@xxxxxxxxxx

Original poster: Paul Nicholson <paul@xxxxxxxxxxxxxxxxxxx>

While I'm in the mood for summarising things, I thought I'd list some of the theoretical myths that seem to keep cropping up in Tesla coiling:-

* Myth: Signals travel through a coil as if they were moving at light speed through the wire.

(They don't. The effective velocity 'along the wire' of a solenoid is given to within a few percent by ln(h/d)*0.39 + 1.19 times c.)

* Myth: Lumped operation is a different thing from distributed operation.

(These are just two levels of detail in the mathematical modelling of coil resonance.)

* Myth: Voltage magnification is much higher than the turns ratio of secondary to primary, attributed to 'resonant rise'.

(The voltage ratio is rather less than the turns ratio due to the limited coupling between the two coils.)

* Myth: Current in the wire offers a different mechanism for energy transfer to the E and H fields.

(It doesn't. Fields and currents are bound together, and a given energy flow (along a coil, say) can be described equivalently using either set of terms.)

* Myth: The low frequency inductance, Ldc, as measured by an LCR meter or estimated by Wheeler, is the effective resonating inductance.

(It isn't. It doesn't correctly represent either the stored energy or the ratio of top volts to base current, because it doesn't allow for the non-uniform current.)

* Myth: The bulk capacitance of the coil, Cdc, (measured at uniform voltage by an LCR meter) is the effective resonating capacitance.

(It isn't. It has the same defects as Ldc because it doesn't allow for the non-uniform voltage in the resonating coil.)

* Myth: High Q factor is important for secondary coils fired from an initial charged primary cap.

(Only a modest Q is required. Output voltage is not proportional to Q as some suggest, but is limited by energy conservation.)

refute. Perhaps others can add to the list from their fields of

expertise? Let's not bother with the numerous myths about

Tesla Himself, nor the inane core beliefs of the many modern techno-

superstitions.

--

Paul Nicholson

--

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