Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

Hi verpies,

great find and read.

Intresting to see that the csr (0.1 Ohm) to measure the drain current can also be in the source lead (Fig. 2-3b).
I thought that would "raise" the MOSFETs source to much from ground.

Also my ringing at 30Mhz at the turnoff time seems to be caused by a LDS (drain-source inductance) (Fig. 2-10 / 2-11).

Will check on that (and read on).

Regards Itsu

[verpies]

Interesting to see that the csr (0.1 Ohm) to measure the drain current can also be in the source lead (Fig. 2-3b).
I thought that would "raise" the MOSFETs source to much from ground.

For small I_D-S currents, you could get away with it.
But do you remember how this current ramped up to 40A when the core saturated?
Well, 40A*0.1Ω = 4V.  This voltage would be subtracted from the gate voltage (V_G-S).
...and your CSR is 4x larger than 0.1Ω so this voltage loss would be 4x higher, too.

To fully turn ON the MOSFET, the gate voltage V_G-S needs to be at least equal to the Miller Plateau voltage (e.g. 10V)

Also my ringing at 30Mhz at the turnoff time seems to be caused by a LDS (drain-source inductance) (Fig. 2-10 / 2-11).

Maybe, especially the inductance of the path between C2 and +V_2B because your C2 is physically pretty far away from +V_2B.
The associated current loop is marked in green color in Reply #840.

[itsu]

While tuning for a max nano-pulse after rebuilding my Drain voltage filters to get rid of oscillations, my little toroid went up in flames.

I was working with 42V on the drain only, so probably there was a short on the magnet wire isolation on the MOSFET side of this toroid.

When checking this toroid i found it was split in half, see picture below

So i had to build a new toroid, now using teflon isolated wire (0.28mm).

I hooked this new toroid up to my shorted Dally coax coil (L3) instead of the dummy 50 Ohm and did some measurements on the L4 coil while pulsing with 1KV the L3 coax coil.

Video here: http://www.youtube.com/watch?v=GYBBSlqDyis&feature=youtu.be

Next i will hookup also the TL494 driver to the L1 coil to see what happens then.

Regards Itsu

[T-1000]

Video here: http://www.youtube.com/watch?v=GYBBSlqDyis&feature=youtu.be

Next i will hookup also the TL494 driver to the L1 coil to see what happens then.

Regards Itsu

This is where it gets really interesting because you are getting signal out of coax cable into all L4 so L1/L2 get it too.
As I mentioned earler now you need to mix two signals comming from L1 and from coax cable and find proper aligment so L4 coil will start picking up amplified summary signal and will start giving out some usable power...

[Alfeen]

Hi all,

as for measuring Mosfet current a shunt in the source line is a much better solution than a shunt resistor in the drain line. However it needs to be in the range of 5 milliohms or even lower for measuring above 10A. Read http://ixdev.ixys.com/DataSheet/99061.pdf pages 7 and 8 for details. 10 amps then give 50mV, which can be displayed on a scope without problems.