It looks like this:

Well thanx Verpies, I don't understand what I'm looking at in those pictures though....

1) 18AWG ....

I would like to understand why this differences between apparently same type of diodes. (I don't expect any answer but if someone has any ...). My 1n5408 provides 10-12ns very easy. 1n5406 does nothing. I'm sure verpies after this (his) test will not recommand 1n5408 as a good DSR diode.
 

When the pulse ....

Basically I was seeing the things in the same way, but my disscusion partners fail to understand the (very important) impendance mismatch.
 
Thank you for both your answers.
 
Mihai

Okay, I'd believe those, but those are representations of a current flowing through the center conductor only....

Hmmm, i think it shows the current and magnetic flux in both the inner AND outer (shield) conductor.


Anyway, i tried severall coax cables as L3 coil, but all 3 behave similar when pulsed with 1.5Kv nano-pulses.

http://www.youtube.com/watch?v=5ah6nXOEcR8&feature=youtu.be

Regards Itsu

Well thanx Verpies, I don't understand what I'm looking at in those pictures though....

You are looking at the magnetic and electric fields inside a coax or a waveguide, pulsed at high CW frequency

DSR is an exotic phenomenon. Diodes used for this were never intended to work in this manner.

Exactly.
Also, a semiconductor manufacturer, that notices this gap in the market, could make a lot of money with minimum investment, by slightly altering their manufacturing process in order to produce diodes especially tailored for the DSR effect. 

The only reason that this hasn't happened, is because this opportunity has not been recognized by fabs' execs yet.

Well failing to get any useful feedback from anyone I went ahead and implemented the circuit.  I got it to simulate at that circuit lab link, adjusted it a little... added some capacitance and resistors to minimize impact on the power supply in overdrive conditions....


and It works great in all the simulations (sorta, LT-spice has a current overflow) but adjusting the rc time delay between the gates causes a good drive... but in reality it fails.


The voltage peeks out at like 1.1V.  I thought I understood these; the gate is a capacitor of sorts, that gets charged to voltage X and enabled conduction; and the conduction from the base is measured in nA so it should be neglegable.  So if I have a capacitor resivoir, it should fill the gate caps, and stop flowing?  Which means that without explicitly pulling to ground the gate, it will float in a semi-conductive state... so basically in the drive side I would think I should see voltages up to 12V.  but I don't and I don't understand.  I so hate hardware; sorta why I stuck with software.


one person threw out what appear to be flippant answers of 'you just can't do that, and anyone should just know' but that 'you need an inverter on one of the gates' ... I'm not sure why or where.


it's just like a vaccuum tube? no?  Put a high potential, and inject another potential from the side to gate current?  Only this shouldn't consume the current from the field?  Or do mosfets really behave the same way, and the stored charge in the gate is consumed in the transfer?

(the failure to get useful feedback wasn't directed exclusively here, is a general annoyance with the world)

Ya; that schematic picture was updated... here's a newer one, was trying to build a PChannel equivalent.


It simulates well; but it doesn't work as well in reality. 
-------------
Correction.  I studied where the shortcomings were after confirming the design.
I had to add a larger capacitor in the R/C delay on the (lower) mosfet; since the lead mosfets only trigger at 1V, the target was set to go to 1/2 voltage, so the secondary was turning on tooo fast.  I increased it to like 10uf and then reduced the resistor.  This has a couple advantages, the (lower mosfet) will drain at a more the same time as the top one.  Was somewhat worried about the turn off condition...


I can now tell that I generate a pulse; will provide more information in a little, wanted to get down the ideas first.


Once the delay between the two leading mosfets is wide enough, the real power driver gates on.  If I measure at the drain, I see a large voltage drop, and I have high confidence that it's going through the coil.  The driving pulse is then I dunno about 35ns.


But then, instead of stopping, it (something, the whole thing everywhere) starts oscillating.  I don't know where this is coming from.  The higher the voltage that is dropped across the driving mosfet, the more this ringing happens.  Now I don't know if it's basically warping the ground reference, so it's appearing to be something that it's not... I got a differential probe; which as I understand it should also be isolated from the scope's ground.   (one of these...) And I have this attached on the secondaries of the small toroid with that attached to a coax cable, and the end shorted (or not).  I've tried two different toroids and the same result happens.... at basically the same frequency but I cannot 100% confirm yet.


See; to retrigger, the capacitor that is used for the driving voltage would have to recharge to a high enough voltage... and it does! so the voltage must be coming from the gate back up through the mosfet pair, and be enough power to trigger it again.


So; does the current through the mosfet also push the capacitor in the gate, thereby forcing the gate extra negative?  something?


I dunno maybe if I record it it will make more sense to me

So I've had this all torn apart for a while considering; waiting for other results.  I started back with the pulse generator; I'm at a loss for a good DSRD that I can buy ; FUF5404 looked good... is any U[tra]F[ast] 400V diode good?  Definatly don't want a smooth recovery diode?  I've also seen it called Sharp Recovery Diode instead of Step Recovery... Using a CSR I think I'm getting a good pulse into my tiny toroid; so back to reassembly.


I put it all together, with the parts I thought I used, and I couldn't even get 150V from the initial toroid.  Had bad resonance on L2, and managed to get about 12V out on L4.  I was in a much better state before, so what went wrong?


------------------------------------------
Sorry if I'm restating all the 'knowns'; just a refresher


First.  TL949 with push-pull power BJT(using E13009 NPN) to drive TR2 ( presumably 220V->12V converter... 3:70 turn ratio, 4 windings, 2 at 3, 2 at 70).


First, shortest duty cycle on the TL949.  This produces a sharp impulse at a wide period.  This allows us to identify frequencies to reinforce for resonance. 


So, need a little more connected.  Want to produce 150V primarily from this, so added a bridge rectifier NTE5322 (25A, 200V, 1.1Vf), with a capacitor on the output.  (Also connected L1, and L2 with a cap, but that just confused the situation, so leave other side open what I thought was L2 ringing wouldn't change when I changed the capacitor, finally disconnecting L1, found I had the SAME ringing).  So, the first ring is between TR2 and the bridge/cap.  If I add a capacitor across the AC input of the bridge, then I can elongate the frequency of the ringing without changing amplitude much.  This helped some, but I still wasn't getting 150V output (very strange, because even a simple joule thief would do that).  Maybe it's the bridge, didn't realize that was so close to tolerance. 


I have to take a break here since I have to experiment there; but, when I connected L1 and L2 with a cap to match the frequency I found after adding a cap across the rectifier, the signal was still kind of weak; then I remembered there was supposed to be a ground connection - to L1.  Connecting ground increased the signal in L1/L2 both.   At certain points ground is important.  I guess attaching the ground though ends up making L1 a half wave, a high potential on one side will go directly to ground, having to reason to overcome impedance of the coil, while a high potential on the other side will ... (reversing terms) draw a current from ground through the coil, while the other side will only draw a current from the ground without going through the coil.  This is sort of a half-wave rectification attaching a ground.


I went back to some of my own videos (good thing I recorded them) and I did have a good square wave resonance on L2, but then that would really mean L2 should be a quarter wave of what it sees in L1  (or a 4x frequency)?


I'm thinking that 1:1 realtionships of all frequencies is not really resonanting.  (like I tuned L2 to the frequency of the ring of TR2 and the cap across the rect/cap...  but it's like not really gaining momentum that way I changed the frequency... I dunno dangling thought there...)


A schematic attempt at the above    



Okay so ya, 70:3 = 23.4 ratio... so easy 12V * 23 = 246V right? no issue.  Oh, but playing with parameters, maybe my inductance is too low; used to work.