Kelvinklämmor

Kelvinklämmor, also known as Kelvin clips or Kelvin contacts, are a type of electrical connector designed to minimize contact resistance. They are particularly useful in applications where precise low-resistance measurements are required, such as in measuring the resistance of wires, cables, or other conductive materials. The principle behind Kelvinklämmor is the use of four points of contact. Two outer contacts carry the current into and out of the component being measured, while two inner contacts are used to measure the voltage drop across a specific section of that component. This four-terminal sensing arrangement effectively eliminates the resistance of the connecting leads and the contact resistance at the current-carrying terminals from the voltage measurement. Consequently, the voltage measured is solely due to the resistance of the component itself.

Kelvinklämmor typically consist of two pairs of jaws. One pair, usually larger, serves as the current terminals. The second pair, often smaller and positioned between the current terminals, acts as the voltage terminals. When properly applied, the current flows through the outer jaws, and the voltage is measured across the inner jaws. This method is a crucial technique in electrical metrology and is employed in various instruments, including resistance bridges and specialized ohmeters. The effectiveness of Kelvinklämmor relies on ensuring good electrical contact at all four points and that the voltage probes are placed on a section of the conductor through which the current is flowing.