I'm gonna check this in the literature tomorrow - I seem to remember that
although the readings you see on-screen on a good DMM, whether numerical
output or simulated analog (the little bar graph thingy that approximates a
moving needle) are "averaged", the min-max feature works differently. Since
it doesn't have to produce real-time displays it records actual minimum and
maximum readings and holds them in memory until one requests them. Thus, if
the V. drops to zero, even for a thousandth of a second, that fact will be
captured by the machine. Or have I been bamboozled?

Incidentally, my meter of choice for years was the Fluke 88, but I switched
to the Blue Point (Snap-On) version recently and I'm regretting it. I
switched because the Fluke display was losing it (couldn't tell a three from
a two anymore, etc.) and figured the cost of repair would be prohibitive.
Also I liked the idea that the BP unit has temperature measuring capability
built in, unlike the Fluke which provides a temp-transducer gizmo -- for an
extra couple hundred clams. But the d*** BP temp sensor was the first thing
to fail, just when the Snap-On truck stopped coming to our neck of the
woods. Again.

> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of David Beierl
> Sent: Thursday, August 26, 1999 4:10 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Which Voltmeter to use?
>
>
> At 14:31 8/26/99 -0700, Coby Smolens wrote:
> >I like David's list, I would add only one thing to the "should-have"
> >section: Min-max record. This is invaluable (read that extremely
> valuable)
> >in finding "drop outs", as in when a bad temp T2 sensor in an
> aircooled van
>
> Yes, wonderful feature, sorry I forgot it.  Just bear in mind that a
> typical digital meter integrates (for this context you can think
> "averages") the input for usually a second or two, so you won't see
> anything that doesn't last longer than that (and will get strange readings
> on values that change faster than that -- that's why the O2 sensor reading
> jumps around on the display when in fact it's varying rapidly but smoothly
> up and down).  Every time the display blinks or updates it has
> completed an
> integration cycle.  If you need faster response than that you're probably
> looking at a 'scope.
>
> The bargraph display that a lot of meters have works faster and less
> accurately than the digital display, but even it takes maybe
> 1/4-1/2 second
> to update.
>
> There are meters with much faster response times, but they are
> $exotic$ beasts.
>
> david
> David Beierl - Providence, RI
> '84 Westy "Dutiful Passage"
> '85 GL "Poor Relation"
>