A microohmmeter is a resistance-measuring device with which low electrical resistance is measured in a DC (direct current) circuit. The unit of resistance is the ohm, represented by the symbol Ω. The resistance of an electrically conductive component in DC is primarily from its geometric shape and its material properties, known as its electrical resistivity, and leads to the ohmic or DC resistance.
The inductance or capacitance of the component is not considered when operating on AC (alternating current). When measuring small resistances, as a benchmark when the resistance is less than one ohm (Rx < 1Ω), there can be noticeable deviation in the terminals that results in measurement error.
This influence can be avoided by connecting in four-terminal technology (Kelvin sensing). Four-terminal sensing uses separate pairs of electrodes meaning that the measurement of the power or current is separated from that of the voltage.« Back