Rosemary Ainslie circuit demonstration on Saturday March 12th 2011

[poynt99]

And for Poynty - when you get back here.  You just need to keep adding to that inductance to get it to a positive value.  And that inductance in turn, relates to the 'added' material to the circuit.  So.  It is my opinion that the actual quantity - the actual material mass of those 'inductive/conductive' components INCLUDING the wire - that allows for more or less 'returned' energy.  Therefore the mass of the circuit components comes into the equation. 

So Poynty.  Perhaps just keep adding inductance to the wires - and maybe you'll get the same results on your sim.  Worth trying perhaps?  Just know that we've actually measured the inductance on the wires to and from the battery to be 3.3 micro Henries.   And I think you can add to the inductance where you replaced the CSR - because clearly that comes into the equation.

Kindest as ever,
Rosemary

Rose,

You may notice that I have been using a total of 4uH of inductance in the battery leads (2uH each side). So I think I am in the ball park. Unless you mean it should be 3uH each side, then I can make the adjustment.

In terms of the wire inductance in Q2's Gate, I've added the same amount I used for the CSR when it was located there in the previous circuit based on the demonstration video, i.e. 200nH. Without that parasitic inductance, the circuit will not oscillate.

You may also notice that the present circuit is essentially equivalent to the previous one. The only major difference being that the CSR is now located in the negative leg of the battery.

Also, I've left out the 200nH of inductance associated with the CSR, but I will show in my next post its effect. In summary, the CSR's inductance has no marked effect on the net average voltage across it.

.99

[poynt99]

WELL DONE POYNTY.  Really good work.  I see now that your results aren't so beneficial.  Does it make any difference if you just up the frequency?

The results are what they are. The frequency is determined by the parasitic components, and is in line with your results as well I believe. The net average CSR voltage is +128mV (equating to about 37W from the battery), so it is leaps and bounds from any negative "benefit". Changing the components to alter the frequency won't change the polarity on the CSR I'm afraid.

.99

[poynt99]

Here are the sim results when including 200nH of inductance in the CSR. The net average CSR voltage is again about +128mV.

I've included a trace for the voltage across the wire inductance. Notice its net average polarity is negative.

.99

[Rosemary Ainslie]

Thanks Poynty.  I looked at the 'average' that your got across the CSR and to me, just eyeballing it - it's more negative than positive.  Can't make it out so clearly across the actual waveform. But the average CERTAINLY should be tending to  a negative result.  Can't think why it doesn't add up accordingly.

The only other adjustment I could recommend is that you take the shunt replacement wire to 2.2 nano Henries.  And if there's still nothing - then, at it's least, the waveforms are remarkably similar. And that there's that 'self generated' oscillation at all is a remarkable correspondence.   Meanwhile I think we just need to sit tight.  I know that there are others who are working on this who also use PSpice.

Thanks Poynty.  I must now just sit back and wait.  I'll post my amended schematic to my report - if I can and I'll download that here today.

Kindest regards,
Rosie

BTW

Each wires' total, I think, is 3.3 micro Henries on each side of the battery terminal.  But I will need to confirm this.  Interesting to see that the oscillations at the wire are all more negative.  I'm sure you just need to factor in more copper.

ALSO - Changed micro to nano

Just posted some nonsense related to the inductance over the shunts.  Hope no-one noticed. 
lol.

[poynt99]

Thanks Poynty.  I looked at the 'average' that your got across the CSR and to me, just eyeballing it - it's more negative than positive.  Can't make it out so clearly across the actual waveform. But the average CERTAINLY should be tending to  a negative result.  Can't think why it doesn't add up accordingly.

You're welcome.

The net average is determined by the sum of the areas of the curve above and below zero. I've painstakingly filled in the POS and NEG areas for you to show this. If you were to cut out these areas from a sheet of paper and weigh them, the red paper would weigh slightly more than the blue paper. This tells us that the net average is slightly positive. See the attached scope shot.

The only other adjustment I could recommend is that you take the shunt replacement wire to 2.2 nano Henries.  And if there's still nothing - then, at it's least, the waveforms are remarkably similar.

I will try changing the wire inductance to 2.2nH from 200nH, but I don't think it will result in a negative average across the shunt.

.99