Four-terminal connections or Kelvin connections are required in these low ohmic value resistors to measure a precise voltage drop across the resistive element. The 4-terminal configuration eliminates the IR-drop error voltage that would be present in the voltage sense leads if a standard two-terminal resistor were used. In current sense resistors the contact resistance and the terminations resistance may be greater than that of the resistive element itself so lead connection errors can be significant if only two terminal connections are used.