DVM recommendation? (LAC)

[Brett Dikeman]

At 11:23 AM -0500 1/17/03, Kent McLean wrote:

>Since my $30 Radio Shaq DVM does everything
>I need it to (or rather, everything I know how to do,
>which isn't much), I'm curious as to what the Flukes
>do that make them worth the extra money.

They are indestructible, accurate, can be (re)calibrated, have a long
warrantee, have a rather good resale, and the service/calibration
manual is included or available(usually free or cost-of-shipping) to
mere mortals.  All the stuff you'd expect from professional test
equipment.

Remember, Radio Shack rebrands stuff from a wide variety of
manufacturers.  You get what you pay for, and for someone looking to
occasionally, when the car starts wheezing, to check one or two
things, the $30 solution is fine, though it probably won't survive a
tumble, it may quit working on you for no reason- I had a cheap RS
mini digital and within a year or two the selector dial wiper
contacts were toasted and the thing would constantly switch modes.

Maybe that bargain basement no-name brand automotive meter works
great for you- and maybe its electronics are built with shoddy,
high-tolerance components with very little in the way of
idiot-proofing.  Good meters take an overvoltage or transient spike
and move on.  Cheap ones go poof.

Look in any mechanic's toolchest and you'll find either a Fluke or a
Snap On, most likely.

We have a 20 year old Fluke handheld DVM; it does voltage,
resistance, and current- the basics; I believe it was a
high-accuracy/basic model, though I think it is true RMS.  The zebra
blocks to the LCD screen needed to be cleaned a few years ago when
the LCD screen went on the fritz, but otherwise, it's had a perfect
service record.

We've considered sending it out for calibration since it has been so
long, but calibration is pretty expensive to justify; the money might
be better spent on a new fluke with all sorts of whiz-bang
features(not to mention more compact.)

Don't hesitate to buy used from a Fluke dealer, btw. Often times the
stuff is available with recent calibration by the last owner.


>   For example, when and/or why is "duty cycle" a nice
>thing to have?

Two examples that come to mind immediately are the wastegate
frequency valve and the ISV.  I know there are several other CIS
valves for which duty cycle measurements are used.

Brett
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