dMM

Digital multimeter (DMM) is a measuring instrument used to quantify electrical values. It combines several measurement functions into one device, typically featuring a digital display and a common pair of probes. DMMs are designed to measure voltage (AC and DC), current, resistance, and, in many models, capacitance, frequency, and temperature. Some provide diode and continuity tests, non-contact voltage detection, and data hold or min/max recording.

Most DMMs are handheld, powered by replaceable batteries, and either manual or auto-ranging. Auto-ranging models select the appropriate measurement scale, reducing user setup error. Resolution and accuracy vary by model, with typical consumer-grade units offering several thousand counts and uncertainties in the percent range, while benchtop units can deliver higher precision. Safety features include input protection, fuses, and category ratings indicating suitability for different voltage environments.

Operation involves connecting the test leads to the circuit under test and selecting a measurement mode. Readings are displayed digitally, and many models offer additional features such as data logging, relative mode, or USB/Bluetooth connectivity for data transfer or analysis.

History notes that digital multimeters emerged in the late 20th century, evolving from analog meters and moving-coil instruments to provide higher accuracy, wider feature sets, and compact form factors. They remain essential tools in electronics repair, electrical installation, laboratory work, and educational settings.

Other uses: the acronym DMM also appears in contexts unrelated to measuring instruments, such as DMM.com, a Japanese online services and entertainment company. In context, DMM typically denotes digital multimeter.