What is your favorite DMM for workplace bench top use? Keithley, Agilent, something else? Keysite, with whom I have no experience? Is BK Precision up to good quality these days?
I need voltage and 2 & 4 wire resistance, and I would probably occasionally use current, capacitance and inductance, but they’re not critical. I do have another meter for measuring down in the microohms and yet another for up in the teraohms, and neither of those needs are high precision, so I don’t think extreme resistance range is that critical. I don’t remember ever measuring voltages over 240 or so. But I have wished for good accuracy in millivolt and sometimes even microvolt ranges.
My preferences are for accuracy (including short and long term stability) and reliability and simplicity of use. I’m thinking maybe 0.01%, 5 or 6 digits. It’s hard to say exactly how much accuracy I need, because it is hard to predict where my future research will take me, but I do keep bumping into worries and limitations with the handheld DMMs I have available, whether accuracy or even just precision and short term stability. I think it’d be preferable to have autoranging with manual override. I actually would like to avoid the more feature rich meters, as their programming and user interface is so much work to learn and remember, and they tend to get into weird modes I don’t recognize. I’m not really interested in logging data or interfacing with computers with the meter (I do a great deal of this but with other dedicated equipment).
I have a Fluke handheld, an 87 I think (maybe it was $300 or $400). It’s at least around 5-10 years old and it’s never been recalibrated. In fact I don’t even know if they recalibrate handheld DMMs, or if the cost is so high one just replaces them. And I need it; I might want to buy another DMM just so I am not without one before sending the old one out. The other day I did a voltage measurement inter-comparison between four handheld DMMs, none of them new or recently calibrated, and without a voltage calibrator (just a 0-30 VDC supply). They all agreed within 1% but not 0.1%.
My precision meter is a Fluke 8840A, which I bought used and had calibrated and certified. I’ve made one repair to it since (bad transformer solder joints), but other than that it’s been perfect.
My favorite benchtop DMM is the Keithely 2001. Very stable, low uncertainty, and has a fantastic user interface. A new one would be out of your price range, though; check eBay. A Keithley 2000 is almost as good and a lot cheaper.
If you want the ultimate in stability and precision, get your hands on an HP/Agilent/Keysight 3458A. A testimony to its awesomeness: it first came out in 1989, and it is still being made by Keysight today. They’re mostly found in electrical metrology labs. We own eight of them.
They definitely recalibrate handhelds. My Fluke goes out for calibration every year (a wast of money IMHO, considering what I use it for, but it’s not my decision, or my money).
I don’t know if it was an 8840 or another similar model (8842 maybe?), but I have used one of these Flukes and it was perfect for what I needed.
Still the most accurate standalone meter out there (at least last time I looked). We would use them for ADC/DAC characterization/debug. There is a National Instruments PXI module that is supposed to be a little better, but PXI is a PITA for the bench (unless you need to automate a lot of measurements).
I have a Hewlett Packard 3478A, too, rescued from a salvage pile years ago. It gives 6.2518 ohms for a 6.25 ohm 0.1% resistor, and they sell these on Ebay, so maybe it’s worth getting calibrated or refurbished.
But it looks to me like the Keithley 2000 is winning…
We use a lot of Fluke, Agilent and older HP meters at work. Have a look around for a used 3478A and you’ll be fine. We send our Fluke handhelds out for regular cals but I suspect they don’t ever really need it. I think I’ve seen one meter come back tit’s up for out of cal and beyond economical repair in 20+ years.
Keithley 2000 won, partly because the user interface looks straightforward and it has RS232 (not USB).
There are lots of good old meters on the market, I know. We have a rule at work against buying used equipment.
I’m amazed at old meters that are working just fine. When I think about the times in winter that I’ve gotten a spark out of static electricity, and working around them, you’d think they would come back with little black spots inside…
