Fourcontact

Fourcontact is a term used in electronics to describe a configuration or family of devices that employ four electrical contacts to measure or drive an electrical signal. In practice, fourcontact configurations separate current injection from voltage sensing, enabling four-terminal or Kelvin measurements that suppress the influence of lead and contact resistances on the measurement.

In a typical fourcontact arrangement for resistance measurement, two outer terminals supply current to the device under test, while the two inner terminals measure the resulting voltage drop. Because the meter senses voltage with its probes separate from the current-carrying path, the computed resistance reflects mainly the device under test, not the contact or lead resistances. This enables accurate measurements even for very small resistances or for materials with relatively high resistivity. The approach is applicable to both direct current and alternating current measurements, including impedance spectroscopy.

Applications include precision metrology, semiconductor testing, materials research, and sensor development. Fourcontact concepts appear in test fixtures, four-terminal sensors, and probe tips used in microelectronic measurement. Variants and implementations range from dedicated four-terminal test probes to specially designed connectors and sensor geometries engineered to maintain a stable four-point path across varying temperatures and mechanical conditions.

Practical considerations for fourcontact systems include ensuring proper four-point geometry, minimizing thermal electromotive forces, and maintaining stable contact pressure. The term is used in specialized literature and can vary in meaning by context but generally denotes systems that separate current paths from voltage-sensing paths to improve measurement accuracy. See also Kelvin connection and four-terminal sensing.