How many turns of 3/8" copper pipe as primary would be needed?

https://youtu.be/XOTLfnMOSqQ?t=661look here at 2200m

it is 8 turns.

but gauge AWG

** 1,** **2** or

**4** electrical wire is perfectly Ok too.

Voltage is determined by turns ratio between primary and secondary not by the gauge.

Here you have calculator:

https://www.teslascientific.com/products/coil-inductance-calculator/keep in mind that Tesla coil is a

radio frequency oscillator that drives an air-core

** double-tuned** resonant transformerhttps://wikivisually.com/wiki/Tesla_coilspark gap to excite oscillations in the tuned transformer. More sophisticated designs use

transistor or

thyristor^{[15]} switches or

vacuum tube electronic oscillators to drive the resonant transformer.

So in early Tariel Kapanadze devices use of spark gap was the easiest way to create wide envelope of suitable frequencies

(at wide bandwidth)

Depends from:

- spark gap distance between electrodes

- voltage delivered to the spark gap

-material used to make spark gap

the Frequencies of very small amplitude growing up to its maximum and that falling down to its minimum

created quite wide top resonance frequencies of few kHz wide amplitude only when:

- given primary winding was tuned by use of capacitor or by puling out/in winds (and by that changing diameter of coil)

So the spark gap by itself made spectrum of frequencies that Have been than shaped/ determined/ dependent

from resonant frequency of primary winding.

However secondary winding has its own resonant frequency-ies ,so function of primary is to deliver electrical potential to secondary.

Because you have ratio of winds of primary vs secondary than like in every transformer voltage at secondary will depend

from that ratio.

e.g if primary is:

- 1 wind/1V than at secondary having 1000 winds (ratio 1:1000) ,voltage = 1000V

and if

- 3 winds/1V than at secondary having 1000 winds ( ratio 3:1000) ,voltage = 333.33V

- 8 winds/1V than at secondary having 1000 winds ( ratio 8:1000) ,voltage = 125.V

so someone may ask

**why I need all of this?**

example:

we have two coil structure Rx and Tx

**.**

if your Tx secondary winding of Tesla coil is in resonance but frequency it is not much stable and is drifting left/ right

than if it is feed by nice good stable generator

**the bandwidth** of this resonance will be narrow.

So Rx( another the same Tesla coil) at some distance from Tx must be sharp tuned to this particular frequency.

But if Rx frequency drifts or Tx frequency drifts than you have no energy transfer from Tx to Rx.

However if you have spark gap in Tx than:

-if Tx drifts than due to wide frequency spectrum created by spark Gap is at high amplitude close to its maximum center and Tx will

transmit at just slightly lower power at closest adjacent frequency to the frequency it drifted from.

Than at some distance we have Rx that can be retuned if needed or just left alone as the energy received is still at satisfactory level.

**Summary:**

spark gap just is easy way to keep Rx - Tx energy level if system drifts.So what is better

** generator or spark gap?**

It depends from how good and stable is your mechanical structure of Tesla Coil in terms of:

- mechanical rigidity

- heat absorption and exchange

- stability of top capacitor positioning

- rigidity of capacitive and inductive elements if your structure.

- preventivness (no streamers, sparks all around)

Note: difficult to read but valuable information is here if someone wants to play with spark gap.

but also ab out structure of Tesla coil and

**coupling ** https://www.richieburnett.co.uk/operatn2.htmlWesley