Using a multimeter safely involves connecting the black probe to the COM socket and red probe to the appropriate measurement socket, selecting the correct function and range on the dial, then touching probes to test points whilst observing polarity for DC measurements. A multimeter is an instrument used to check for AC or DC voltages, resistance and continuity of electrical components, and small amounts of current in circuits. By doing so, a multimeter can help you achieve a. Whether you're figuring out why a light switch isn't working, testing a battery, or building a robot, knowing how to use a multimeter is a fundamental skill. more The Engineering Mindset tagged products below. Start with the highest range available on your dial—typically 750V for.