On any given day you can find a miniature multimeter in my pocket. These devices are the equivalent of a Leatherman for electronic enthusiasts. (The Leatherman would be in my other pocket.) Most of the time, I want to check the voltage of a deep-cycle battery in my electric-vehicle or troubleshoot a problem with a solar photovoltaic system. But multimeters do things like current measuring, resistance and continuity, which make them handy for solving problems ranging from home wiring to electronics repair. (For more on what do do with one, check out Ladyada's multimeter tutorial on adafruit.com). I've used a number of "portable" units over the years, and while many are anything but, one jumps out as my solid favorite. Here's my take on a few popular units.