milivolts

Millivolt (mV) is a unit of electric potential equal to one thousandth of a volt (0.001 V). The milli- prefix denotes 10^-3. A millivolt is commonly used to express small voltages in electronics and instrumentation.

In practice, millivolts describe signals from many sensors and transducers, where the raw electrical output is small and requires amplification before processing or digitization. Instrumentation amplifiers or precision op-amps are routinely employed to boost millivolt signals while preserving signal integrity and minimizing noise.

Examples of millivolt-scale signals include temperature sensor outputs and biomedical measurements. Some temperature sensors, such as the LM35, produce about 10 millivolts per degree Celsius. Thermocouples generate voltages in the millivolt range for temperature differences, although their sensitivity is typically tens of microvolts per degree Celsius. In biomedical contexts, electrocardiograms (ECG) are typically a few millivolts in amplitude, whereas electroencephalograms (EEG) are usually in the tens to hundreds of microvolts range.

Measurement and conversion: millivolts are read with voltmeters or analog-to-digital converters (ADCs). For reference, 1 millivolt equals 0.001 volts, and 1000 millivolts equal 1 volt; 1 millivolt also equals 1000 microvolts.

See also: volt, microvolt, ADC, instrumentation amplifier.