Re: how to change Q

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

Original poster: "Shaun Epp by way of Terry Fritz <twftesla-at-qwest-dot-net>" <scepp-at-mts-dot-net>

Hello Cory,

>From my college days Q=XL / R   which is the inductive reactance of an
inductor ( i.e.. your secondary) divided by it's resistance.  It is known as
the quality factor also.

Now at resonance  XC = XL  so either will do.

Resistance varies by the gauge of wire you use and its length.   R=pl/A
which reads rho(resistance constant of the metal)*length/area of the
conductor.

XL=2*pi*freq*inductance.

Inductance is mu(inductance constant) * number of turns squared * area of
the coil / length of solenoid  L=u * N^2 * A/l

So we can lower the resistance by lowering the gauge number of the wire,
this increases the diameter of the wire, but this also require a longer
solenoid for the same inductance, This will increase Q.   We can add more
turns of wire to the solenoid which makes it longer and increases
inductance, but the form factor gets bigger: larger form factor means that
all the available energy can't be coupled into the secondary, Q goes up but
it wouldn't perform as well.    Or increase the diameter of the secondary,
this increases inductance, maintains the form factor of hight vs. width.
This method is suppose to be the best.  Heavier gauge wire and larger
diameter secondary!!

Some of this information I learned for "Modern Resonance Transformer Design
Theory"
Hope this helps,
Shaun Epp

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, March 30, 2002 11:06 PM
Subject: how to change Q


> Original poster: "Cory Roussel by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<imcuddlycory-at-yahoo-dot-com>
>
> Hello all,
>
> How do you change Q?  from my understanding it is "the
> sharpness of resonancy".  or the exactness you need to
> get to make something resonate- but how can you change
> that? reduce resistance?
>
> thanks everyone,
>
> Cory Roussel
> G1206
>
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