In the usual Max measurement, the input (current) is sampled and the maximum
sample is displayed, but the true maximum could have occurred between the
samples and in that case you miss the true maximum or inrush current that
your looking for. In inrush current measurements first off it's a triggered
measurement and measures for a very short period of time and it doesn't
depend on samples, I think it's an analog approach.

Shaun

After a short phone conversation with a tech support person at Fluke, I think
I understand the difference: it's the acquisition speed. (The new clamps also
have triggered event feature, but that's icing on the cake.)

In the clamp meters in Fluke's present product lineup that have the "In-rush"
feature, the acquisition speed is listed as 100 mS. In the older clamp meters
(eg. my model 36) that have the "Max" feature, the acquisition speed is
listed as 250 mS.

In other words, old (model 36) meters sample 4 times a second. New (model
33x) meters sample 10 times a second (overhead aside).

Help me understand the implications of the faster acq. speed. Obviously for a
quick event to be measured, the speed needs to be quick or the event will
pass unnoticed. Having said that, as long as the event overlaps *any* period
of time with the acquisition window, the peak value will be measured. Yes?
It's kind of a random chance of getting the acquisition (for events
acquisition speed) isn't it? But not impossible.

Thanks,
Dave