mV

mV stands for millivolt, a unit of electric potential difference equal to one thousandth of a volt (1 mV = 0.001 V). It is used to express small voltages in electronics, sensors, and physiology. The prefix milli- denotes a factor of 10^-3 in the International System of Units. The volt remains the SI base unit for electric potential, voltage, and electromotive force.

In electronics, many sensors and signal chains produce or require millivolt-level signals. For example, thermocouples and strain gauges may generate tens to hundreds of millivolts, and operational amplifiers are often used to amplify signals into the volt range. Digital multimeters and data acquisition systems commonly measure and display signals in millivolts or volts, with appropriate scaling.

In biology and physiology, millivolts are used to quantify electrical potentials across cell membranes. Resting membrane potentials in many neurons are around −70 mV, and action potentials involve rapid shifts on the order of 100 mV peak-to-peak. Microelectrodes are used to record these voltages, which are typically much smaller than a few volts.

Common conversions: 1 V = 1000 mV and 1 mV = 0.001 V. When dealing with such small voltages, electrode impedance, grounding, noise, and temperature can affect accuracy, so proper shielding and calibration are important.