Claimed OU circuit of Rosemary Ainslie

[TinselKoala]

.99's simulations show that the spikes and ringdown can be seen on the voltage directly across the load as well.
But how does one monitor this trace and the current trace at the same time, since the ground references are different?
One needs a completely isolated scope, I suppose.

Also the scale difference makes the ringdown hard to see. If you are showing a 24 volt signal, and the spikes and ring are only a few volts +/- that 24 volts, you need to do the blowup like .99 showed.

But if you monitor the load like I do--Point A wrt negative rail--, you can use the AC coupling feature to remove the 24 volt DC offset, and then use much more amplification of the vertical scale, to see the detail in the spikes and ringdown much better.

Of course, to do this one needs to understand the offset and the coupling features, and to remember that the "zero" of an AC-coupled trace isn't necessarily at zero volts.

[TinselKoala]

And of course my current trace looks quite like that as well. My risetime from the pulse generator is around 5 ns.
I think I have more inductance than you are using in your sim.

Try pumping the load inductance up to a more realistic 100 microHenry if you have a chance...

I see spikes in my current trace that aren't showing up on yours. Plus the switching time of the mosfet is again getting in the way here. If you use a faster switching mosfet you will see more spikes, more voltage, more of everything "good" in the circuit.

[poynt99]

OK, if I am interpreting the posts right, Hoppy says he is using the probe tip at the positive rail side of the load and the probe ground at the other side of the load. But that's not what .99 said. But you are agreeing...

Isn't the "Drain" equivalent to "the other side of the load" 

I have ALWAYS used the Ainslie points A and B, simultaneously, which of course requires that the channels use a common ground, that is, the negative rail.

For our own clarity to be sure we're all on the same page (and I think we are), point "A" is simply the battery voltage, and point "B" is simply the shunt voltage...agreed?

If that is the case then the RA clan never measured the load voltage, which is what Hoppy and I have done with the scope shots.

.99

[MileHigh]

TK and .99:

I agree about sticking to the paper's measuring points to compare apples to apples.  How much ringing and spiking you observe will be dependent a lot on the battery's input and output impedances.  I assume that if you use a full-sized car battery then any ringing or spiking would be brought down to the millivolt range.  It certainly would not hurt to "add value" and do a true coil-resistor voltage measurement also.

That first plot of the shunt resistor voltage is interesting.  I am trying to figure out what causes that little dimple at the end.  In fact all of the plots are rather impressive.  Are you adding any wire cap-inductive effects also?  Or do you just give it a certain length of wire connection and PSpice models the capacitive and inductive effects per cm or something?

MileHigh

Big pee ess for Rosemary and Aaron:  Look at the zoom-up on the coil-resistor discharge in .99's post #947.  Do you see how the voltage across the coil-resistor goes to about -0.8 volts at the end of the main pulse for a while?  That's the inductive part of the coil-resistor DISCHARGING THROUGH THE DIODE.  Try to force that one into your collective brains.

[poynt99]

You've done everything correctly TK. Just showing another point in the circuit.

I can also show all the voltage effects across the battery if I introduce an accurate value for the battery impedance/resistance. However I can show current effects without having to do so, and I believe I did show scope shots of current ringing on the battery V+.

Carry on Maestro 

.99