CFN Metal Foil Current Sense Chip Resistors Bourns CFN Metal Foil Current Sense Chip Resistors help to provide improved heat dissipation and higher reliability due to larger terminations and solder joint surfaces. The series is constructed with a metal foil resistive element mounted on a ceramic substrate for excellent heat conductivity. Applications for Bourns CFN metal foil current sense resistors include current sensing, power supplies, stepper motor drives, and input amplifiers.