hi howard, yes no conversion to farads and henries.  much easier, and 
it works.  i don't remember where i found it, but i have used it for 
years.  after when you are taking a test, use the easiest formula 
possible.  when doing all the conversion stuff its easy to make a 
mistake.  i remember when i took all my fcc exams i took them at the 
fcc office and they read the exam to me and i had to do the math in 
my head, no calculators were allowed back in those days.  take it 
easy, c u mike w6quv



At 08:43 AM 1/18/2012, you wrote:
>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