Owww,...first pic surprised me!!

Very dense board and cool to see that Bluetooth chip in there. The display has a quite robust cover. Those were exactly the weak point of those cheap "yellow multimeter" which I used to have.

Jan Cumps  Very cool.  I remember building a multimeter from a kit when I first got into electronics.  It was very helpful in understanding how the meter really worked.  It's quite a different story now with IC based meters.  They also do a lot more than the old ones.

I'm going to do a few measurements - to try out some of the specifics of the meter.
A Digilent / TI Analog Shield and some resistors act as test devices. Keithley DMM6500 as reference for measurements.

DC Voltage

+2.5 V reference. The two meters probe at exact the same point.

Goal is to view how close the measurements are, not how good the reference (LM4128) is.

3 resistors

I can't use the two meters together because they 'd influence in this case.
I've left the resistor part the same for each measurement and swapped the leads at the meter side.

10 K

1K8

470R

in VA mode, where the current and voltage is measured and the VA (this is DC, so equals W) is derived.

The 2nd display flashes between V and A.

Hi Jan,

Nice on-screen display. 

The 121GW seems to have a slightly out-of-spec measurement on the 470 ohm resistor? (I did not look at the other readings, but this one looks out of spec). If the Keithley instrument is assumed to be almost spot-on (I've not checked the accuracy spec of that), then the reading should be  460-463 ohm (approx) on the 121GW meter (or have I misunderstood.. it is very likely I've not thought of something).

I can try on my Keithley meter and a 470 ohm resistor if you like, but I don't have a 121GW (but I have some other meters, e.g. $50 to $150 ballpark)

I have some new probes to try out (Pomona 6344).. just got them last week from a Project14 shopping list. They seem fine, except the long pointy attachments are excessively long, and hard to use on the end of the already-long main probe body. (Also, they are not this colour (in case it makes a difference : ) It is a much darker grey in reality, compared to the photo which looks very light grey).

(Image source: Farnell)

shabaz said:

The 121GW seems to have a slightly out-of-spec measurement on the 470 ohm resistor?

I noticed it too. I used the same leads for both measurements.

I use these DMM contraptions:

1. a number of standard but decent banana cables. A few colours to help understanding the setup, but most are black and red.
2. The leads that come with the 121GW. Teflon. Can be converted to pin and banana. With a CAT-IV protector hat
3. Hirschmann grabbers. Very old - 80s. I use these a lot. They can take a banana lead or a wire.
4. generic crocodiles. Can also take banana or wire
5. The leads that come with the Keithley DMM6500
6. leads with a set of different screwable ends. Not good but handy
7. pointy pins from Philips. Also from when I went to school in the 80s. I bought them from one of my classmates together with the grabbers
8. the legendary jw0752 biting probes. They are used a  lot when probing SMD PCBs.

shabaz said:

except the long pointy attachments are excessively long, and hard to use on the end of the already-long main probe body.

I read in Pomona's datasheet that  "Extended slide on tip adapter fits directly over probe, allowing testing of hard to reach test points".
It may come in handy when measuring inside a device where you can't take out the PCBs, or to reach the base plate in a plug-in modular design. Although maybe a length heat shrink on most of the exposed pin would be good to reduce risk of mishaps?
It's what I use #7 for in my photo above.