[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Strange sweep results
Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
Hi Shad,
On 18 Jun 2002, at 18:46, Tesla list wrote:
> Original poster: "Sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<sundog-at-timeship-dot-net>
>
> Hi All,
>
> I have a strange problem. I got my new signal generator (B&K 4001), and
> it works like a champ. My scope is giving me some fits (must be jealous),
> but everything is working now.
>
> I immediately swept one of my small 2.5" coils. And got the expected
> Fres of around 833khz. Sweet. But, upon winding the generator up a bit
> more, I ended up with another spike at 2.5mhz.
>
> I'm a bit confused. At harmonics I get a nice double-sine waveform,
> with a big and small hump. I've seen it a million times sweeping coils,
> but never have I seen a smooth sine wave out of the secondary for anywhere
> except resonance. It's strange allright. I can't make heads or tails of
> it. I know that Fres is 833khz, that's about what it works out to when I
> do it by hand, and that's what the sweep tells me.
By double-sine waveform do you mean one that looks like Fr modulated
by a much lower frequency - like the waveform you get when energy
trades between the primary and secondary? You shouldn't actually see
that when sweeping a secondary alone (I presume that's what you were
doing?). Or were you feeding the generator into the primary while it
was coupled to the secondary and doing the sweep? How was the
generator connected up? And the scope?
> Normally, on a harmonic, the amplitude of the input sine is far less
> than it is at resonance, but this one is just as strong as the real
> Fres. I'm confused now. Should I set my tank frequency to 833khz or
> 2.5mhz? Or should I try both and see which gives better performance?
I'm confused too. Can you describe your measurement technique in more
detail (a diagram would be wonderful).
Thanks,
Malcolm