Re: Prefered resistor range

From: Larry Brasfield (donotspam_larry_brasfield_at_hotmail.com)
Date: 03/16/05 

Date: Tue, 15 Mar 2005 22:49:00 -0800

"The Phantom" <phantom@aol.com> wrote in message
 news:b3gf31tfc7k5gbukrkb5kfe29hjde93bc1@4ax.com...
> On Tue, 15 Mar 2005 19:58:14 -0800, "Larry Brasfield"
> <donotspam_larry_brasfield@hotmail.com> wrote:
>>
>>Tables are used only for certain limited arbitrary data
>>and to correct for those few results that do not agree
>>with the publish tables when computed algorithmically
>
> Have a look at the little Basic routine I posted. Whoever
> originally wrote it did a good job of curve fitting and came up with a
> formula (algorithm?) that properly calculates those oddball values
> that a simple root-of-10 method doesn't get right. Thus you don't
> need any tables.

I copied it for later study shortly after you posted it.
There is an interesting mix of both the straightforward
logarithmic decade splitting and some adjustment via
a cubic polynomial. It is quite a tangle, analytically.
I suspect it was quite a trial and error effort rather
than founded on anything like the original algorithm.

If it covers the whole set of tolerances without any
corrections, I will be amazed. But using that kind of
method is very fragile against changing requirements.
Using tables judiciously can make for better code. 

-- 
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.
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