Digital Multimeters (DMM) or Digital Volt Ohm Meters (DVOM) as they are also commonly known are very widely used in the automotive industry, and are the most generally useful testing tools. In the hands of a qualified operator the DVOM can be used to diagnose very complex problems in vehicle electrical systems, however some of this testing work has been shortened or eliminated with the introduction of on-board diagnostics and the use of scan tools.
There are several types of DVOM available at different price points. The more substantial and usually more expensive types have more functions and are generally more reliable. In some locations many meters are known more commonly by their brand name.
The DVOM is an electronic measuring instrument that combines several functions in one unit. The most basic instruments include an ammeter, voltmeter, and ohmmeter.
The meter usually has a central rotating selection switch which is used to select the electrical test function that the meter is going to be used for, and a set of input points that are used to connect the meter to the item/circuit being tested by test leads. Most meters also have a safety fuse fitted (of about 10 amps maximum) for operational safety and to prevent damage to the meter should it be connected to excessive electrical loads.
Some additional features available in some multimeter units: