microsiemens

Microsiemens (µS) is a unit of electrical conductance in the International System of Units (SI). It represents one millionth of a siemens, since 1 µS = 1 × 10^-6 S. Conductance is the reciprocal of resistance, so substances with high resistance have small conductance and are measured in small units such as µS.

In SI practice, conductance is expressed as siemens per meter (S/m). In many applied fields, conductivity is reported as microSiemens per centimeter (µS/cm) or millisiemens per meter (mS/m). Because 1 cm = 0.01 m, 1 µS/cm equals 1 × 10^-6 S per 0.01 m, which is 1 × 10^-4 S/m. In other words, 1 S/m equals 1,000,000 µS/m. Also, 1 µS equals 1 × 10^-6 S.

Applications: µS is widely used to quantify ionic content in liquids and characterize low-conductance materials. In water quality, electrical conductivity measured in µS/cm serves as a proxy for total dissolved solids and salinity. In physiology, tissue conductivity is expressed in µS to study ionic transport. In electronics and materials science, µS figures help describe leakage paths and sensor responses.

Measurement: Conductivity meters rely on temperature compensation because conductivity varies with temperature. Calibration uses standard solutions, commonly potassium chloride, to ensure accuracy. The microsiemens scale provides a convenient range for low-conductance measurements, with larger scales used for more conductive samples (mS and S ranges).