Ideal for those into basic electrical repairs and maintenance is the Extech DM110 pocket multimeter. This compact DMM is a cheap alternative to full range multimeters and provides a decent backup, or ‘beater meter’, for pros when working smaller jobs. Examples of tasks it would be useful for might include: automotive, appliances, basic electronics, general DIY.
- Pocket sized
- Auto ranging
- AC/DC voltage to 500V
- AC/DC current to 400mA
- Measures resistance to 40MΩ
- Measures capacitance, frequency and duty cycle
- Integrated test leads and rubber boot
- Sizeable, clear display
- Auto power-off
- Relative mode and data hold
- Size: 4.25″ (108mm) x 2.2″ (56mm) x 0.5″ (11.5mm)
- Weight: 1.7oz (48g)
- Battery (CR2032)
- Rubber holster
- Carry case
- Instructions (DM110 manual)
In-depth Review of the DM110
This is one of Extech’s cheaper meters; an American brand that typically churns out higher spec’d devices. The DM110 has most ranges, however, including voltage, milliamps, resistance, capacitance and even frequency and duty cycle. With these ranges, you can do most things, including basic HVAC work.
The best of it; the Extech DM110 is an auto ranging multimeter, so you don’t need to take the time to chase individual ranges. It will select the correct range of its own accord, and while not lightening fast at this, it beats picking out separate values on a manual ranger.
As with most pocket meters, though, it is an averaging RMS responder only, so you wouldn’t get accurate results when measuring variable speed drives as you would with True RMS. This would not be an issue for standard AC systems.
There are a couple of modes on the DM110. Relative mode lets you compare results with a stored value (from 0). It will also allow you to zero out the natural resistance within the test probe leads. In addition is a data hold function, for freezing the present on-screen reading.
The small size of this meter is its biggest boon. At around half an inch thick and a few inches high, it is easy to whip out of a toolbox or pocket and start measuring. The integrated leads, while not good practice on full range multimeters, add to the lack of hassle factor.
|DC voltage||400mV / 500V||±(0.7%+3) @ 400mV||0.1mV|
|AC voltage||4V / 500V||±(2.3%+5) @ 400-500V||1mV|
|DC current||40mA / 400mA||±(2.0%+5)||0.01mA|
|AC current||40mA / 400mA||±(2.5%+10)||0.01mA|
|Resistance||400Ω / 40MΩ||±(2.0%+5) @ 400Ω-400kΩ||0.1Ω|
|Capacitance||4nF / 200μF||±(3.0%+15) @ 400nF||0.001nF|
|Frequency||10Hz / 10MHz||±(2.0%+5)||0.001Hz|
|Duty cycle||0.1% to 99.9%||±(2.0%+5)||0.10%|
It’s not the most accurate pocket multimeter on the market either, but is good enough for most general work.
Design and Build
Many pocket meters have rudimentary (or no) protection, though the Extech DM110 at least has ergonomics in mind, with its ribbed case. The rubber holster protects the corners of the meter and has probe lead clips built into the rear. The case itself is basic, with a central dial selector switch, four rubber buttons and no jack socket inputs – since the leads are integral.
Interface and Function
The display has a resolution to 4000 counts, or 3 3/4 digits. It’s fairly high contrast and comes with useful icons, such as range type, low battery indicator, and over range limit. There is no backlight on the display, but then you can’t really expect it on such a basic device.
Battery: The battery is a button cell type (CR2032), which is included with the purchase. To conserve power, an auto-off feature comes into play after about 30 minutes of non-use. Not all pocket meters, and indeed full size meters, have this useful battery-saving function.
Protection: The Extech pocket mini multimeter cannot measure high current and is un-fused. It does come with some input protection, though, rated to CAT-II @ 600V. This gives it surge protection value in the 4kV range. The Category II designation means it is not suitable for measuring mains current directly. It is okay for testing the mains within an appliance, but not to the socket outlet or circuit breaker itself.
Pros and Cons
- Nice size
- Relatively large display
- Okay resistance, capacitance and frequency ranges
- Relative mode
- Fairly cheap
- Short, integral probe leads
- Doesn’t measure amps
- Rated CAT-II only
The Extech DM110 Review covers a basic pocket DMM for those into standard DIY work, such as motorcycle or car electrics, testing batteries or basic circuit boards and power tools.
Alternatives: There are a slew of other pocket meters out there, with the Amprobe PM55A a significant notch up. Yet the DM110 is quite cheap and does pretty well. The Craftsman Mini is similar to the DM110.