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Secondary resonance freq
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From: Vivian [SMTP:V.C.Watts-at-btinternet-dot-com]
Sent: Saturday, June 06, 1998 6:01 AM
To: Tesla List
Subject: Re: Secondary resonance freq
SNIP
>
>----------
>From: Marco Denicolai [SMTP:marco-at-vistacom.fi]
>Sent: Friday, June 05, 1998 1:11 AM
>To: tesla-at-pupman-dot-com
>Subject: Secondary resonance freq
>
>I measured yesterday the resonance frequencies of my secondary. It is a
>4.3" diameter PVC tube, winded for a length of 19.7" with AWG 26 wire.
>I got the following results:
>
>324 KHz
>813 KHz
>1475 KHz
>1766 KHz
>2053 KHz
>
>These without any top toroid or sphere. I used a function generator (sine
wave)
>and oscilloscope.
>
>I was waiting to measure the fundamental and all odd harmonics (x3, x5,
etc.)
>but can anybody explain to me how I have got the above readings?
>
Hello Marco,All,
You don't say how you connected the function generator and oscilloscope.
The classic way is to feed the base of the coil with the sig gen then drape
a wire connected to the scope near by and tune for Max radiation and hence
reading.
My computer program calculates your resonance at 337 kHz so 324Khz is
definitely the fundamental.
If your sig gen has a 600 Ohm output impedance (i.e. on the high side) I
find it better to scope the output of the sig gen. You then tune for a null
or minimum signal. The secondary coil, as a series resonator becomes and
acceptor circuit and loads the output hence the signal goes down. The
advantage of this method is that you get much less mains born modulation on
your scope. Also you get much less pickup of other radiation which can
confuse the reading. Make sure the secondary is away from any primary
circuits or other coils.
regards
Viv Watts UK.