What is a Multimeter?
Multimeters are commonly used to measure current, resistance, or voltage. Originally termed analog Volt-Ohm-Milliammeter (VOM), some models are referred to as Volt-Ohm Meters (VM). Digital Volt Meters (DVMs) measure voltage (certain oscilloscope models have this capability, as well).
Digital multimeters are popular models, but multimeters are available in analog or digital formats.
Analog multimeters feature traditional analog display, moving trends, and peak adjustments without precise digital DMM value. They also offer low impedance DMM – a distinct advantage in the measurement of electronic circuits, but they will not load the circuit.
Stray / Ghost Voltages
Low impedance analog multimeters have the ability to check for the stray or ghost voltages that are caused by space between de-energized wires and adjacent energized wired. Analog meters load circuits, dropping the needle to zero.
DMM Stray / Ghost Voltage Solutions
High-quality DMMs have a rotary or similar switch with low input impedance for AC voltage measurements. DMM-lowering accessories are available to lower impedance, as well.
Digital multimeters display digital values and convert analog measurements, providing a higher level of accuracy and resolution that analog meters. Select DMM models feature uncalibrated analog bargraphs that match the needle capacity of analog meters.
How should I choose a digital multimeter (DMM)?.
Today’s digital multimeters include greater measurement and feature capacity, for use by electricians, HVAC technicians and DIYers. Clamp meters concurrently measure voltage and current, and pocket multimeters feature the added convenience of portability.