Rosemary Ainslie Circuit Demonstration June 29, 2013 Video Segments

[TinselKoala]

TK,

I don't see any pattern at all in that Fig.8 scope shot. But without a description we can only speculate.

We can speculate, and also experiment. Try setting your PG for a triangle ramp, tilted over to the left, with about 50 percent of it above the zero reference, at a frequency of about 31 kHz. You should see displays like 0183 and 0184 with your timebase set at 50 us and 10 us per div, respectively.

Now, change the timebase to 500 us/div and see what the screen looks like with the FG at 31 kHz and at 10 kHz.

[MileHigh]

Poynt:

That was a great clip, a home run for sure.  "From the point of view of the battery itself" comes to mind.

Nice to see you cut to the chase.

I confess that in the last round of discussions I wasn't considering the ground loop issue.  Even way before that I was thrown off by the scope channel common ground issue.  I am sensing atrophy.  lol

I was even a bit surprised that you went right back to the battery.  That's because I was kind of self-brainwashed in the sense that we gave up on that issue with Rosie a long time ago.  We just couldn't convince her of the "battery distance problem" and more or less dropped it.

You made a very educational clip for all to view.

A bit of colour commentary:  The reason the parasitic inductance is so important here is that the current is always going start-stop start-stop at high frequency in the lengths of wire.  Just like we are all familiar with the back-EMF spike from a coil when you disconnect it from a voltage source, the same principle is happening in the interconnect wire itself.  It's like there is a mini back-EMF spike happening all along the length of wire from the switching.  That mini back-EMF spike is from the wire itself, and not the battery.  As we saw in the clip that will have an affect on the measured CSR voltage and also on the measured battery voltage - a double whammy.  That screws up the measurement.  The solution is to go back to the battery and avoid these mini back-EMF spikes.  They don't exist when you are directly on the battery because there is no more wire length to worry about.

MileHigh

[TinselKoala]

Ooops.

[profitis]

thers definitly going to be a back-spike out the nichrome yes,this is what we want to harness.

[poynt99]

Thanks MH.

Apologies for the shadowy DMM presentations and uncooperative probe issue, but this wasn't rehearsed and I know I'm not particularly well-skilled as a live presenter. The hope is however that the main points get across.

Yes I see Rose's forum is shut down for the moment...didn't pay the bill? Or more likely they exceeded the traffic allocation due to constant hammering of all those netbots?

Good thing I've been posting here as well.