David Nelson-5 wrote > This link was posted over on Insight Central and I wondered if it > might help for those wanting to check the accuracy of their DMM > voltage readings: http://geoffg.net/Voltage_Reference.html. It looks > quite simple and am thinking of making it just to see how my meters > are doing.
This is more or less how I check my meters for accuracy, and I suspect most practicing EEs do the same (certainly no one I know uses a Weston cell!). I like to test at 1.25V and 2.5V to see if there are any linearity errors. If the meter reads off by more than 1% then I send it in for calibration, otherwise I keep on using it. The Fluke 179 that I bought 3 years ago (with NIST calibration) has not deviated more than 0.5% (using 0.1% voltage references) while the el cheapos I got from Harbor Freight (mainly for the bead thermocouple) wander as much as 5%, especially with a change in temperature. I also test the DC mA range by inserting a precision (0.1%) 125 ohm resistor in series with the reference voltage. Same stability with the Fluke; same wackiness with the el cheapos. David Nelson-5 wrote > Jeff, are you implying that if I want reasonably good voltage > measurements I'd be better off with a non-clamp meter? I have an > Extech EX830 so don't really know how accurate it is. > >> On Wed, Sep 25, 2013 at 7:34 AM, Jeffrey Jenkins >> And for mV accuracy don't even think about a clamp meter... Voltage >> readings >> on them are more or less an afterthought, even for the Flukes. Implying? More like bluntly stating! ;) More specifically, my Fluke clamp meters only resolve down to 0.1V, while my 179 DMM resolves down to 0.001V (ie - 1mV) on the 6V scale. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/AC-DC-amp-meter-tp4665328p4665348.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
