RE: [TCML] DRSSTC weird waveform behavior

[Justin B <boshjack@xxxxxxxxxxx>]

Steve, as a response...

> 
> This is all fine, though you do need to be careful about the scope probe
> inductance picking up voltage induced by the large fields near any of the
> primary conductors.  This induced voltage is usually 90 degrees out of phase
> and can make your voltage measurements (particularly the parts that should
> look flat) look funny.  Anyway, you are going about things "correctly" from
> my point of view.
> 
> 
  This may be a case seeing theres primary wires going all over, obviously when scoping the output of the CM300, theres a primary wire really close to the probe.  Same when scoping other parts of the bridge.  Also seeing that the primary rests 12" or so above the bridge too.  The driver however, does not quiet yet have any type of shielding to it, which shouldnt matter much in these cases because im doing low voltages, so the secondary shouldnt be inducing and fields to screw stuff up.  I have done scope readings on the GDT input and output, and things look as it should, no ringing either.  I did though order a few variable inductors so I can at least find a sweet spot and go from there.  It is good to hear things sound like they are correct, thanks.
> 
> I think you said you had a resistor of several K ohms with the inductor?
>  This is far too large for practical tuning.  For example, i use about 50
> ohms with a 50uH inductor for obtaining enough phase lead for CM300s.  Any
> more resistance that the network looks too resistive and you dont get enough
> phase lead.  So unless you are using a really huge inductance here, than
> anything over a few hundred ohms is gonna look mostly Resistive, and not
> produce much phase lead at all.  Id suggest getting something like a 200 or
> 500 ohm pot in there, and at least 50 to 100uH inductance.  You know, you
> can actually calculate the phase angle if you review how complex numbers and
> phasors work (or look it up).
> 

I currently ordered a 1K 25-turn pot last sunday.  This would mean 1 turn is 40 ohms, or 1/4 a turn, 10 ohms.  Figured this would be fine enough to get fine tuning to adjust the phase.  If I need more, parallel a resistor to the pot is always an option to give me a lower resistance range adjustment.  Sadly I do not own an LCR meter so I can measure inductances, So I just have what inductors I have laying around or can wind by hand.  Else, I do have those variable ones coming in the mail eventually.  But yes, it would be correct to say I had a 10K 15-turn pot in series with the inductor.  Thats why I got some 1K instead after noticing how small of an adjustment range I had for adjusting the phase, way too etchy!  Oh well, I should hopefully be able to clean stuff up with the combination of variable 1K pots and variable inductors.  May be awhile until I get them, so there's not too much I can do at this  time sadly.
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