[Prev][Next][Index][Thread]

Re: another version of frequency formula

A
>
>The above formula does not take into account the coiling of the wire. 
>Written in similar terms to the above, the formula I posted becomes:
>
>	  c                                 (1/5)
>F = ------------------------ x (5/4) x (H/D)
>     4 x length of winding
>
>
>c=speed of light
>H=height of coil
>D=diameter of coil
>
>Nothing special. Just highlights the difference due to coiling the wire. 
>For an H/D=10, the two forms differ only by a factor of 2.
>
>
>SOrry to beat a dead horse.
>-Ed Harris
>
>
>Ed,
        The length of wire as measured in what units? Inches, feet, meters ?

Jim Leonard
---------------------------------------------------------------------
Jim,

	The one nice feature of the above formula is that you can use 
whatever units you want as long as they are consistent. For H and D all you 
need is the ratio which of course is unitless. If you choose the speed of 
light as c=3x10^8 meters/sec, then choose the length of the winding to be 
in meters so that the frequency will come out in Hz=1/sec. Alternately, you 
could choose the length of the winding in miles and c=186,000 miles/sec and 
still get the frequency in Hz.


Eg. as Mark B. reported, his giant coil has the followinf dimensions:

H=11ft
D=4ft
length of winding= "about one mile"

     186,000 mile/sec                       (1/5)
F= -------------------- x (5/4) x (11ft/4ft)
     4 x 1 mile

F= 71000 Hz

This is close to the self resonant (no top electrode) frequency he
 reported (correct me if wrong M).

As I said before, it works well on all the coils I have made as well as all 
the coils Malcolm so gernerously reported on.

-Ed Harris