Claimed OU circuit of Rosemary Ainslie

[PaulLowrance]

But, both have a common problem, and that is the shunt inductance. The filtered high-side shunt effectively eliminates this problem, and is one reason it was chosen.

If your shunt resistor has that much inductance, then I agree with that! Geez my man, grab a carbon resistor and get this over with. If you don't have it, then parallel higher values. 

Paul

[PaulLowrance]

I'm going to state the bottom line here as things seem to be shaping up now that I've taken a few measurements with my new LCR meter.

Calculating current from a voltage probe measurement across a shunt is futile. The 4" probe ground lead itself has 0.15uH of inductance, and combined with the 0.12uH inductance of the shunt resistor, this is more than enough to skew the real current measurement in the circuit as I have shown in the simulations.

Why not use a carbon resistor that has no appreciable inductance???

I might add that my "cheap" inductance meter isn't worth much at all for low inductance measurements. The load resistor I've been using all along was measured to be about 29uH, whereas now with the new Kelvin meter, the inductance is actually 10.9uH.

You're not talking about an air inductor are  you? Both meters probably apply different levels of pp voltage. Permeability of all materials is non-linear with respect to the applied field. Exp., near saturation the permeability is low. Place a magnet near the inductor and the inductance changes, unless you're talking about an air inductor.


Regards,
Paul

[poynt99]

They're complaining that the 10000 uF caps might be shorting out current spikes, and they have good reason to believe so. A good testing method minimizes the influence on the DUT, and those caps fail at that. No offense, but placing 2 10000 uF caps is just not that professional. That's why from the start I recommended using an op-amp with low pass filter.

My 2 cents. Sorry if I'm getting a bit frustrated because this is a one day test job at most. More like 1 hour. 

Paul

Paul, I disagree.

You can see in the test plan that I am using a lab power supply. As such, adding more filtering to its output is no more detrimental to the DUT than the supply's own internal filter caps which are doing much the same thing. The filtered shunt is essentially just additional output filtering.

Any energy that finds its way back to the supply will do so whether the supply is a battery or a heavily-filtered lab supply, and I have clearly shown this is possible and does occur in the PSpice simulations. In fact one simulation test I ran not too long ago and posted here showed that the pulse from the inductive collapsing field returned about 6% of the supplied energy back to the source (an ideal source with Zo=0), while at the same time contributing 6% of the total energy dissipated in the load resistor.

.99

[poynt99]

Why not use a carbon resistor that has no appreciable inductance???

You're not talking about an air inductor are  you? Both meters probably apply different levels of pp voltage. Permeability of all materials is non-linear with respect to the applied field. Exp., near saturation the permeability is low. Place a magnet near the inductor and the inductance changes, unless you're talking about an air inductor.


Regards,
Paul

Paul, the problem is more than just the shunt resistor inductance. There is inductance in the probe ground lead, and it can be quite appreciable, such as 0.15uH for a 4" lead. Double that for an 8" lead, which some folks may be using in their testing.

In my PSpice simulations, as little as 0.3uH of inductance will significantly skew the voltage and hence current measurement, as the reactance becomes quite appreciable (with 50ns rise times) relative to the DC shunt resistance.

Regarding the load resistor, yes it is a ceramic air-core as shown in the test plan and photos previously posted here.

.99

[PaulLowrance]

Paul, I disagree.

You can see in the test plan that I am using a lab power supply. As such, adding more filtering to its output is no more detrimental to the DUT than the supply's own internal filter caps which are doing much the same thing. The filtered shunt is essentially just additional output filtering.

Well there's your problem my friend. You're not using a battery.     I recall Bedini saying in one of his circuits that the secret is in the battery.

Any energy that finds its way back to the supply will do so whether the supply is a battery or a heavily-filtered lab supply, and I have clearly shown this is possible and does occur in the PSpice simulations. In fact one simulation test I ran not too long ago and posted here showed that the pulse from the inductive collapsing field returned about 6% of the supplied energy back to the source (an ideal source with Zo=0), while at the same time contributing 6% of the total energy dissipated in the load resistor.

The problem is that fundamental spice does not simulate true transmission line propagation. It takes a lot of work / tinkering (lot of custom modeling) to get some true transmission line effects in spice. What you see in spice is assumed to be instantaneous transmission, but that is not the real world. In the real world there are propagation delays, line reflectivity due to impedance mismatching, phase, etc. mostly at higher frequencies of course. Conventional science knows of a lot of noticeable effects occurring in normal circuits that contain for example non-air inductors, if you have the proper equipment to measure such effects. For example significant noise produced by Barkhausen effect, which is significant at 400MHz on up into the GHz region. There are programs that model transmission line propagation, such as antenna modeling software; e.g., 4nec2 . I'm not defending the Ainslie circuit, but if we're going to be open minded, then we should at least give Ainslie the benefit of the doubt, and test her circuit. If she says we should use a battery, or do not use those large capacitors, then that's what the tester does, no?

So, if there are high frequency energetic pulses traversing the wires, the 10000 uF caps could easily absorb such energy. You will not find that effect in spice unless you specifically know about the effect and model it, but good luck with that. 

Paul