Re: [TCML] Thumper, the worlds most advanced tesla coil.

[Michael Twieg <mdt24@xxxxxxxx>]

You're correct that directly clamping the burden impedance will screw things
up, but that's not what I'm doing.  The clamping diodes are connected to the
burden impedance through a 1K resistor, so the diodes do not significantly
load the CT and the phase lead is not affected, regardless of the amplitude
of the signal.  I wish I could post a schematic, but apparently the mailing
list doesn't support attachments (not sure if my last email got through at
all).

-Mike

On Fri, Jun 11, 2010 at 1:00 PM, Finn Hammer <f-h@xxxx> wrote:

> On Fri, 11 Jun 2010 14:27:44 +0200, Michael Twieg <mdt24@xxxxxxxx> wrote:
>
>  So I tried messing with the hysteresis network on my comparator, and I
>> added
>> some extra shielding, but still got poor results, so I went ahead and
>> whipped up a variation of your predictor.  I think there are two things
>> desirable in a zero crossing detector:  a large dv/dt at the zero
>> crossing,
>> and the appropriate amount of phase shift, which should be constant over
>> amplitude.  So I just made a LR shunt like yours, but used a large burden
>> resistor (10ohm) to give a large signal, then clamped it with diodes to
>> limit the signal to a range acceptable by my comparator.  Circuit
>> schematic
>> attached.
>>
>
> You will not get any leading current signal if you clamp with diodes.
> Inductor must be allowed to enjoy full swing of signal, otherwise it doesn't
> work.
> You should try to do a simulation, and see.
>
>
> Cheers, Finn Hammer
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