Low resistances (milliohm or sub-milliohm) are more & more critical to measure nowadays. For such resistance measurements, a method called Kelvin probing allows very accurate results. To accomplish this there are two leads, which provide a current source across the load to be measured, and two more leads across the load, which provide the sensing…. There are different ways to contact this leads, here are 2 different medium to establish contact between IC & PCB: Elastomer & spring pins.