121GW Multimeter

I'm a huge fan of Dave Jones and his EEVBlog website and YouTube channels, and followed the development of this meter with a lot of interest and anticipation. The feature set in this meter was specifically designed by Dave to meet his requirements & desires for a reasonably priced meter that focused on electronics testing and troubleshooting. This was one of his pet projects, and the resulting meter is perhaps the best value for money in a mid-range meter. In fact, this meter does some things better than some much higher priced meters. Here's what I particularly like:- build quality is excellent- regular firmware updates that are easy to install- data logging to an internal SIM card or...- data logging via Bluetooth to a really slick Android or iPhone app- fast continuity latch times- very well done documentation that is updated with every firmware release (both the documentation and firmware updates are downloaded from Dave's EEVBlog website)- the meter has been tested and certified by Intertek (a UL equivalent), which means it actually meets its 600 volt CAT III protection rating- it measures temperature- the supplied test leads and thermocouple are high qualityAre there any negatives? One or two minor gripes. First, in the design phase Dave struggled to get the meter squeezed into the small form factor he prefers. I'd say this to Dave - don't be afraid of large meters! Embrace the big! The layout on this meter is somewhat cramped. Next, being red/green color blind like much of the world's male population I find the red secondary function markings on the dial hard to see - REAL hard to see. Dave, if you are thinking of changes to an upcoming production run of this meter I'd recommend changing the secondary function markings to something easier to see - perhaps yellow?At the end of the day all I can say is this is a great meter, particularly for the price. It sits on my bench and gets used almost daily for troubleshooting and kit building. Highly recommended.

I've watched EEVBlog for years now, and Dave Jones is more than just a Aussie voice on YouTube. He's a skilled electrical engineer, and this definitely shows. The bluetooth connection to your phone just works, with no hassles. It's well done, accurate, and really my only gripe is that it's a bit on the chunky side. However, since mostly what I'm doing is the oddball voltage check with a portable unit, it's entirely acceptable. It's not like I'm a field engineer who needs something small and portable.

The meter seems nice enough. The test leads are worthless. They didn't come with tips. The came with the HV tip covers but not tips. It's not what I expected from a meter in this price range. Amazon has a bad habit of not checking their returns and not catching people stealing parts (or alternatively they know it's missing parts and don't care). I can't recommend this meter as good for anything but sensing temperature. The thermocouple seems to be functional. I didn't need a temperature gauge, I needed a meter.

Fit, finish and function great! Size is great the bench for all you get.

Note that firmware for this meter is still evolving, from v. 2.02 in the first review, to v2.04 available now. The user manual has also been updated, to V5, Mar 1 2020.It is not obvious what the developers focus was; it's neither fully electronics-oriented (lacking inductance or transistor measurements) and limited capacitance utility for typical RF work. For caps under ~ 1 nF, it needs work.It is also not meant for applications where voltage is significantly greater than the common 220/240v mains range. But the developers have taken great care to incorporate safety and overload characteristics needed for the upper range of its spec'd voltage. Their concern is evident; attention to fuse rating details, and a caution to avoid using auto-ranging AC voltage when DC voltage is also present is now described in the updated manual. Incorrect auto-ranging can cause wrong readings and potentially lull the user into improper use.For the price, it has very good voltage, current and resistance accuracies, and the 50,000-count resolution (except for capacitance) rivals the better bench-top multimeters, but adds portability.I was disappointed in the meter's capacitance capabilities, and I'll go into some detail the reader can understand what they might find.My unit was apparently typical in that it would not read values under 100 pf accurately. It required about 50 pf to read 0, which seemed to be about a constant offset for higher values. It 'should' be possible to calibrate the meter to minimize or eliminate negative offset, but there's no clear worked-out guidance for doing this without risk of bricking the meter. A positive offset can be zero'd with Relative mode. My solution for negative offset was to solder an appropriate-value capacitor across the poles of a duplex banana plug/jack . That worked well.The capacitance function is limited to 10,000 count display, vs. 50,000 for other parameters. If there's no cap attached, manually setting the scale presents an inscrutable display units meant to indicate scale. This makes manual scale setting inconvenient at best. O.FL≠OF.L,, etc.Capacitance ranges change in normal factor-of-ten fashion up to 100 uF full scale, at which the range increments by a factor of 100, at the 'up to 10,000 uF' full scale.Capacitance resolution is 10 times better than indicated in the manual, but given the offset for small caps and the odd scale jump at 100 uF, it isn't entirely useful unless you make your own provisions.For capacitors in the range of a few hundred uF (e.g., 470 uF), the display resolves only 3 digits, which leaves an order of magnitude of potentially better resolution unused, and this for capacitances which wouldn't be affected by offset. At just over 100 uF, even 1% resolution seems appropriate given the 2.5% accuracy spec - until the count uncertainty is also considered. At 5 counts uncertainty, accuracy is reduced to about 6-7% for capacitance a bit over 100 uF. In Autoscale mode, range changes don't necessarily coincide with the scale's maximum value, and show some hysteresis, changing range at different points going up scale vs. going down scale.Some of the finer points of operation are not described in the manual. This might reflect an expectation that users should already know enough not to need certain info. For example, an offset nulled using Relative mode works only on that scale, so can't be used with autoscale, or if another scale is manually selected. However, Relative mode can be used if one first measures the component on auto-scale and then selects manual mode, which locks the meter on the needed scale.In diode check mode, any number of beeps will occur, with no mention what they mean. Seemingly random beeps and boops.Some minor annoyances:The display plastic cover is thick and not uniform in thickness; its refraction distorts the view of the display. In conjunction with the top surface curvature, glare adds to the difficulty reading the meter display unless the backlight is turned on, which is probably the major hit on battery life.An improvement is to use a non-reflective adhesive film, such as those you buy for your cell phone. It's not a huge improvement but is easy enough and avoids having to use the backlight in many situations.Speaking of battery life, using the backlight wouldn't be an issue except that the manual deprecates use of rechargeable batteries. Seems an odd limitation given present technology. You might want to use rechargables anyway if you plan to use the backlight to any extent. Very fine scuffing of the top surface can reduce reflection glare and refraction distortion. If you get carried away and scuff too coarsely, a finer grade sandpaper followed by plastic polish can fix it, but a cell phone protective film is a better solution.The meter has a fold-out stand, but it's difficult to use effectively due to curvature of the case bottom. The meter is laterally unstable; I'm thinking about hot-melt gluing a horizontal stabilizer at the case bottom. It could really use a cradle with a flat bottom so the meter could be reclined to improve visibility, without compromising stability.This review is now nearly 4 years old. In the interim there have been many newer high-count DMMs enter the market. I can't give advice about them, but am certain that many would suit as well. Were this meter to be re-designed today, it would almost certainly have a Li-Ion rechargeable battery with external power via a USB port.Gluttons for punishment will hem-and-haw over new meters, probably failing to make a good trade-off between their time investment looking for "newer-cheaper-better". The choice does not need to be considered permanent, because there will likely be better choices next month or next year!

Awesome meter. :)

I got this for $200, normally retails for $250 or so, and I gotta say it way exceeds expectations. If you need a serious multi-meter for electronics work, this should be very high on your radar. Worth every penny.