TT Electronics/IRC provides their OARS-XP series metal element resistors, with the ability to withstand high surge currents and extreme temperature cycling environments. The devices are specified for PWM control circuits and motor controllers as well as fault detection and power factor correction (PFC) circuits.
The OARS-XP series resistors consist of a flameproof 0.25 inch wide metal element resistance alloy welded to compliant copper terminals designed to compensate for the TCE (thermal coefficient of expansion) mismatch between the device and the PC board. Unlike other resistor technologies, such as thin film/thick film chips or foil devices, the alloy used in the open air metal element provides stable resistance values that will not experience degradation of performance at extreme temperatures (even at high temperatures). Its unique open-air design allows the heat to be dissipated into the air rather than conducted to the PC board where thermally-sensitive components are located.
