Mike,

I like your formula, it is easier to work with, however, for it to work so 
the answer comes out in megahertz, one must realize that the  L needs to be 
in micro henrys and the C in pico farads.

See, with all this discussion, I even learned something.

 73's

Howard #3

----- Original Message ----- 
From: "Mike Cozzolino" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 18, 2012 10:24 AM
Subject: Re: Math Help


> hi david, i read through both of your postings, and the formula i
> gave scott is very short and gives you the same answer.  try this out
> and see if it works for you.  the formula is: f=159 over the sqrt of
> l times c.  where the c is in picosarads and the l is in
> microhenries.  so 50 times 200 = 10,000 the sqrt of 10,000 is
> 100.  now take 159 devided by 100 and you get 1.59 mhz.  a lot
> simpler and no conversion.  try it out and see that it works.  also
> remember that when you are talking about inductance and the symbol
> for microhenry is uh and the symbol mh is millihenry.  and you have
> farads then microfarads then nanofarads then picofarads.  take care,
> c u mike w6quv
>
>
>
> At 05:29 AM 1/18/2012, you wrote:
>>All,
>>
>>Sorry for my previous post, I previously stated that 1 picofarad = 1 x
>>10 ^ -9 Farad, which is why my calculation was wrong.  I also screwed
>>up entering the units on the calculator, so I should have
>>double-checked my work!  I believe this is correct, however:
>>
>>The formula is:
>>
>>Resonant Frequency (Hz) = 1 / (2pi * sqrt(L C)
>>
>>where L is in Henries and C is in Farads.  So, in your example:
>>
>>1.  Convert 50 microHenries to Henries, 1 microHenry = 1 x 10^-6
>>Henries, so 50 microHenries = 5.0 x 10^-5 Henries.
>>2.  Convert 200 picofarads to Farads.  1 picofarad = 1 x 10^-12 farads,
>>so 200 picofarads = 2 x 10 ^ -10 Farads.
>>3.  Now, plug into the formula:
>>F = 1 / (2pi * sqrt (5 x 10^-5 times 2 x 10 ^ -10)
>>= 1 / 2pi * 1 x 10^-7
>>=1591557 Hz
>>
>>Hopefully this is correct now, and hopefully I did more than just
>>muddy up the waters beyond all hope!  My apologies!
>>
>>So you can see, the worst part of this problem is getting the units
>>correct, at least for me.
>>
>>73,
>>
>>David Thurmond, KK4ADV