Kapanadze Cousin - DALLY FREE ENERGY

[itsu]

re the scopeshots:

Not all the critical information is contained in the "numbers in boxes" of the DSO's screen.

Thanks for the tips TinselKoala, i will try to comply,  Regards itsu

[mihai.isteniuc]

Greetings 2 all

I have re-done my measurements using the same setup as previous (my previous post), but this time using a 5ns time scale osciloscope. Measurements done thin the probe settings at 10x, osciloscope settings: 25ns time scale, 5v/div.

Attached it's a screen with my real dsrd pulse. It's still quite far from what it should be but I think I know how to improve it.

Regards,

Mihai

Later edit:

The load was 47 ohm resistive (not the coaxial cable)

[verpies]

I have re-done my measurements using the same setup as previous (my previous post), but this time using a 5ns time scale osciloscope. Measurements done thin the probe settings at 10x, osciloscope settings: 25ns time scale, 5v/div.

That's a voltage trace, isn't it?

It would be more informative if you posted the current trace through the DSR Diode.
It is important to see how long the diode conducts in the forward direction and how long it conducts in reverse.

[mihai.isteniuc]

@ verpies.

Yes it's the voltage trace on the point where the coaxial cable should be on a 47 ohm resistive load (I think the 47 ohm resistor it's winded so actually the load was much higher) Hoppy was right when he said that the pulse it will shrink even more when the load it's attached to last dsrd diode. Also my condenser at this point it's 1.5 nF (instead of 1 nF). There are many minor deviations from dally's design:

the ring has 6x5x3 dimensions
the avalanche diode it's not the KD203A it's a romanian model 25N10 rated 25 Amps 1000V.
i'm using a mosfet transistor and mosfet driver bettween the nanopulser and the mosfet.

In reality thirst test I was conducted was with only 9 turns on the scondary of the toroid (my main consern was not to distroy the osciloscope with high voltage) and the pulse was actually much wider, around 50ns or so, but i forgot to take a picture of that pulse. After adding 3 more turns you can see the result. The pulse was shrinked from 50 to 38-40 ns. I believe that my 1000V diodes has a higher capacitance then kd203a so I have to increase the voltage (both primary and secondary) to charge faster the capacitance and really go under 10ns pulse (I hope), or change both dsrd diodes, or a combination betwen this setups at least until I will have the KD203A. For the time being it's ok with me. Also using a pure rezistive load (or the coaxial cable conected may help ... will see)

Regarding your request it's hard for me at this point to do the measurements because I don't have full time access to that osciloscope. Will see when I can use it again.

Mihai

[verpies]

@Itsu
Here are the annotations of the scopeshots that illustrate the influence of the resistors between the UCC27511 driver and the gate of the IRF840, while the drain of this transistor is loaded with 10Ω resistor and supplied with 40V.

Note that if the pulse shown by the red trace was representing the drain current then the polarity of that pulse would be the opposite.
In other words - the source-drain voltage pulse is inverted in respect to the drain current.

P.S.
For an explanation of V_A and V_GS(th) see Fig.12 on page 17 of the attached Application Note.