Ross said:
I snipped your reply so to save the NG's wheel mice since it was fairly
long....
You recommend a fluke 110 which is a bottom line fluke meter but would
probably suffice. I cannot find it for under a $109, though that is what I
found in a few moments of Googling. I have, on my bench, a true RMS Fluke 32
that I paid $69. My Google searches show it at $79 now at rapid electronics
and it is true RMS. You are correct on the fact that a true RMS may be
necesary to measure PC's. Since I have never owned anything else, I am not
sure what the error or difference would be.when measuring computer current.
I would never purchase a $3 meter for anything accept simple tasks such as
automotive etc... I would venture to guess that putting decent leads on it
would be more than the cost of the meter. This is one of those discussions
where the focus changes from the OP and centers on the example. By the
questions asked it appeared to me that the OP would not get through the
resistor/shunt method and the clamping method would be the best and the
safest. I want you to know, I was not trying to be rude or argumentative but
just had some questions. Some of which you never answered. When you jumped
in, you were siding with DarkMatter, who has a big flame going with me
currently. So, just by your comments, you somewhat became involved. You
*must* know that! Stick accross the monkeys cage?.....Ok maybe not...
One other comment. The clamp you chose was high end and the meter you chose
was not...both would have certainly worked but as far as the comparison
goes....It was only supportive of your claim and not realistic as I see it
(for what that is worth, and you may think that is zilch...and that would be
fine too)
I think I substantiated my claim here that good DMM's are more expensive
that good amp clamps......Ross : >)
On the $3.00 meters - they are certainly not something
you want to rely on for precision or long life. That
said, they might surprise the hell out of you! I bought
4 of them to use when I was designing a little DC-DC
converter where I had to track DC input volts and current,
and the dual DC output volts and current. I needed 6 meters
simultaneously, with the scope monitoring the input and
output wave forms and I varied the input voltage and
the output loads. The precise output voltage and current
was unimportant, I just needed to know when an output
fell out of regulation, so a change on the meter was the
indicator. Once I established the relative points, I could
move the Fluke to get accurate readings. Surprisingly, as
it turned out, they were accurate enough.
On the Fluke meters - I picked the cheapest true-RMS
DMM and the cheapest true-RMS clamp on that I could
find in the Fluke line - I was not slanting the
selection - I couldn't find a lower priced clamp
on in the Fluke line. The Fluke 32 has been
discontinued and replaced by the one I specified -
the 335. See:
http://www.tequipment.net/FlukePriceList.html
The model 32 you quoted at Rapid Electronics
http://www.rapidelectronics.co.uk/limited/85-0102.htm
is 79.00 GBP - pounds, British currency.
It translates to 145 US dollars, so it still costs
36 dollars more than the DMM, and that does not
include shipping from the UK.
I thought I answered all of your questions, but
if I missed some let me know what they were and
I'll try to answer.
I'm aware of the flaming - I wish there was none.
Some people enjoy it - I don't. I don't want to
take sides or contribute to any flaming.
If you want to discuss the flaming aspect further,
I'm willing to do that by E mail. In fact, I would
have initiated E to you about that if your E mail
was valid.
Finally, I apologize for misunderstanding the
points that seemed argumentative to me, and I'm
glad to hear they were not intended as such