fyraelektrodförbindelser

fyraelektrodförbindelser, also known as four-electrode connections or Kelvin connections, are a method used in electrical measurements to minimize errors caused by contact and lead resistances. This technique is particularly important when measuring low resistances, where the resistance of the connecting wires and the contact points can be significant compared to the resistance being measured.

The principle behind the four-electrode connection involves using two separate pairs of electrodes. One pair, often referred to as the current electrodes, is used to pass a known current through the sample or device under test. The second pair, the voltage electrodes, are positioned independently of the current electrodes and are used to measure the voltage drop across a specific portion of the sample.

By measuring the voltage drop only across the voltage electrodes, the influence of the resistance between the current source and the voltage measurement points is eliminated. This is because no current flows through the voltage measuring instrument itself, so the voltage drop across the voltage leads and their contacts does not affect the measurement. This results in a more accurate determination of the true resistance of the material or component.

Common applications of four-electrode connections include measuring the resistivity of materials, characterizing the resistance of semiconductor devices, and in precise resistance calibration. It is a fundamental technique in many scientific and engineering disciplines requiring accurate low-resistance measurements.