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Inductance (fwd) [correction]




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From:  Jim Lux [SMTP:jimlux-at-earthlink-dot-net]
Sent:  Friday, April 03, 1998 12:52 PM
To:  Tesla List
Subject:  Re: Inductance (fwd) [correction]

Tesla List wrote:
> 
> ----------
> From:  Hollmike [SMTP:Hollmike-at-aol-dot-com]
> Sent:  Thursday, April 02, 1998 6:54 AM
> To:  tesla-at-pupman-dot-com
> Subject:  Re: Inductance (fwd) [correction]
> 
> Malcolm,
>    I would be interested in seeing the reference source that gave you the H/D
> at one for max Q.  I have an old electrical engineering/radio communications
> handbook that gives the D/H ratio of 2.45 for the mas inductance which is in
> fair agreement with 2.222 which Erik worked out.  I also worked this out a
> couple of years ago and got the same result as Erik(gave me something to do on
> a long boring road trip).
>      Perhaps this 1:1 ratio is better at certain frequencies or some other
> conditions that I am unaware of.  The real goal is to get maximum Q.  Whether
> or not this corresponds to max inductance(and apparantly it doesn't by what
> you are saying) is interesting.  I tried to figure out all the variables that
> affected the Q and thought that maximizing the inductance was the best way to
> improve the Q.  I would appreciate it if you could elaborate on this.
> Mike Hollingsworth

The Q would largely be determined by the resistance of the coil winding, which in turn is a big function 
of the wire diameter and frequency (i.e. skin effect) (and of course the material... A coil of Nichrome 
will tend to have low Q).