This handheld instrument, also known as a Volt-Ohm meter or VOM, is used to measure electrical current, voltage, frequency range, and resistance in wiring systems, electronic equipment, appliances, and batteries. They are available in both digital and analog forms, and can range in price from ten bucks to much more depending upon their applications -- some multimeters also measure decibels, temperature, and frequency in hertz.
The average DIYer, however, can get away with an affordable option. With a little bit of practice, you can use a multimeter to troubleshoot electrical problems, from testing battery life to checking the workability of broken extension cords and appliances. When touching the two test probes to a device, the meter can reveal poor connections, broken parts, and loss of power when contacting a circuit. (Please note that reading the user manual prior to use and applying common sense when working with electricity is very important in injury prevention and general safety.)