All very good points. I haven't had any problems, either.
However, the OP should also keep in mind what kind of signal is being measured. An inexpensive meter can be very accurate measuring pure sine wave AC or a nice steady DC, but once you try to measure complex signals like PWM, all bets are off. A good Fluke will measure the true RMS value of the signal, but other meters could show very different results depending on how they average the constantly varying signal. Some might only sample periodically and miss peaks or valleys. Others might use diodes and capacitors such that they measure the peak DC voltage even if the average is much lower.
Pat
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Monday, December 22, 2014 12:22 PM
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Re:Inaccurate volt meters
I have used the inexpensive digital panel meters for years and not found them to be significantly inaccurate or unreliable, as verified by using a good digital meter. But they need to be wired thoughtfully, as nicely shown in Capt. Mike's blog. A large source of errors can come from using a "common return" point away from the source of what you are measuring. Additionally, using shielded twisted pair wire where you need to put the meter a distance from the measurement point can be helpful to shield the input to the meter from electrical interference which can lead to inaccuracy.
A quality digital meter is the best investment you can make. A basic Fluke can be had for around $150 and will last a long time. The two Flukes I have, going on 30 years, are still as good as when I bought them!
John
Flatwater Electronics
www.flatwaterfarm.com
"Neurosurgery for computer looms."
Posted by: "PISQUE1969 ." <surv69@gmail.com>
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