Millivolt

A millivolt (mV) is a unit of electric potential difference equal to one thousandth of a volt. It is a subunit of the volt in the International System of Units (SI). The prefix milli- denotes 10^-3, so 1 V = 1000 mV and 1 mV = 0.001 V.

Millivolts are commonly used to express small electrical signals in instrumentation and sensors. Many sensors, such as thermocouples, chemical sensors, and strain gauges, produce voltages in the millivolt range that require amplification before processing by electronic circuits.

Thermocouples may generate tens to a few millivolts across practical temperature ranges; other sensors likewise produce millivolt-level outputs depending on the measured quantity. In electronics, millivolt signals are often the input stage for instrumentation amplifiers and analog-to-digital converters, with subsequent amplification and conditioning to interfaces that operate at higher voltage levels.

Measurement and processing purposes typically involve voltmeters or digital multimeters, and often require amplification by operational amplifiers and careful shielding to minimize noise before digitization by an ADC. The small magnitude of millivolt signals makes precise measurement sensitive to grounding, interference, and temperature drift, necessitating good design practices in instrumentation and data acquisition systems.

For context, the microvolt (µV) is a smaller unit (0.001 mV), while the volt (V) is the standard, larger unit of electrical potential.