i-Pod-sized DMMs comply with safety ratings to CAT II at 600V, CAT III at 300V
By Dan Strassberg -- EDN, December 17, 2004
Meterman Test Tools’ $27.95 to $49.95 PM-series DMMs (digital multimeters) measure just 2-1/8×4½×½-in., including a protective rubber holster. According to the manufacturer, the size without the holster is the same as that of Apple Computer’s (www.apple.com) i-Pod music player. Moreover, the less-than-3-oz meters have controls that are similar to those of the i-Pod. Notwithstanding their ability to fit comfortably into a shirt pocket, the units meet UL CAT II safety standards at 600V and CAT III at 300V (Picture). They also provide transient protection to 4 kV and overload protection to 450V.
A key to achieving the safety ratings without sacrificing the size was attaching the test leads directly to the meter; no plug-in jacks are necessary. (You can replace the leads, however, in the same way you replace the batteries; you open the case, which requires removing one Phillips-head screw.) To achieve the diminutive case dimensions, Meterman made no compromises in the size or legibility of the 4000- or 6000-count (depending on model) display. The 0.6-in.-high digits, which—for the sake of battery life are not backlit, are easy to read under a variety of lighting conditions.
Operating the controls is highly intuitive once you get the hang of holding down the one button for two seconds to turn on the instrument. In fact, you usually don’t need to manually select the operating mode; if you fail to choose a mode, the AutoTect feature on two of the three models automatically selects ac volts, dc volts, or resistance. Autoranging units also select the range for you. To conserve battery life, the units shut off if you don’t use them for a while. On two of the models, A VolTect feature allows detecting the presence of ac voltages without probing the conductors. The units measure capacitance to 3000 μF. Two of the units measure frequency to 30 kHz and ac and dc current to 2000 μA. The top-of-the-line unit also includes a zippered carrying case. All units carry a one-year “no-hassle” warranty.
Meterman Test Tools, 1-877-596-2680, www.metermantesttools.com.
