How To Buy a DMM

Thumbnail Guide to Digital Multimeters from Absolute Beginner's Guide to Building Robots A digital multimeter (DMM) is an extremely handy tool to have around for any sort of electronics work, from testing to see if the current is actually off in your house, to finding out how much power is left in your MP3 player’s batteries, to finding out the value and state of components for your electronic projects. A multimeter has “multi” in its name because it contains a number of different measuring instruments for testing electronic components and their processes. Some DMMs are more “multi” than others. The most basic features usually include: ■ Direct Current (DC) Voltage Measuring — Tells you how many volts (or how much electrical potential) are available. Expressed in volts (V). ■ DC Current Measuring — Tells you how many electrons (the little beasties that make electricity possible) are racing through your circuit. Measured in amps (A). ■ Alternating Current...