Pulsing A Bifilar Coil And Collecting From It And Various Ways Of Going About It

[Jimboot]

One more thing.... Not sure if this was brought up before...

The total for both coils is 35mh  The sifi individual coil were 13.5mh and the bifi were 9mh each.  The calculated resonance for the bifi using 35mh and 16.4nf is 6.1khz and the scope shot is 12.98khz.  So I recalculated for 9mh which is each windings measurement and we end up with 13.1khz.  So we have to only use the inductance of 1 bifi winding and the total capacitance to calculate the resonance of the bifi. 

Seems like there is an oddity there. Like the 2 bifi windings maybe ignore each others inductance at resonant freq? ?    new puzzle part?   In series it measures just like the series sifi coil, but apparently at resonance the working inductance of the bifi is 9mh.

Mags

Edit: my msg was lost somewhere.
That's a nice low frequency mags. I have not yet measured inductance. My ribbon TBP is ringing at 447k(sine) & 450k(square) Yellow is across a 100k resistor in series. Blue is across pocket Vellemann SG running off its DC charger.

[Magluvin]

The rigol gives a lot of info.  Nice

Mags

[Jimboot]

The rigol gives a lot of info.  Nice

Mags

Still working out how to use it. Let me know if you want anything measured! These are good experiments for to learn its functions that's for sure.

[Magluvin]

Im finding that you can reliably calculate the res freq of a bifi coil by reading its winding to winding capacitance and the inductance of just 1 winding and run it through an LC calculator. It seems most are running the coils to find the res freq then calculating that with the total series inductance to come up with the capacitance. Need to look into it further. That way doesnt give us a tangible capacitance that we can verify. But here with just using 1 winding inductance and the inter winding cap value, I am getting a .1khz accuracy at finding the res freq without testing. 2 coils tested and next will be the big pancake I made. If it works there also Id say its conclusive and we need to look at these coils a little closer.

Also, was just playing before I go home to eat, if we have the bifi in series, when we only operate 1 winding  and leave the other winding attached at the middle and its other end free, the single working winding will resonate at the bifi res freq. Didnt know that.    So if we are working 1 winding only and the far end of the other winding is loose, what inductance should we be looking at now?

Lots of stuff to do.  All this stuff is very simple testing n probing. And Im finding things I never thought I would find.  Very interesting coil indeed.

Mags

[evostars]

pulsing the coil, like ringing a bell. short high voltage infinite small rise and fall time, hairpin pulses, like the hammer that rings a bell.

I use this, and highly recomend it:
http://www.rmcybernetics.com/shop/cyber-circuits/pulse-modulator-ocxi
It gives these hairpin pulses, if the impedance of the load is small enough.

Best would be pulsing the bifilar coil, from both ends, with opposite polarity. (discharging a capacitor with both leads at the same time).
It could be done with a relais, charging both leads at one possition, and discharging both leads into the coil at the other possition.