PWR221T-30-4R70F is a TO-220 style power resistor manufactured by Bourns using thick film on alumina ceramic technology, designed for current limiting, capacitor discharge, and current measurement circuits in power supplies for telecom and industrial applications. The resistor features a 30 W power rating at 25°C case temperature, low inductance of 0.1 µH maximum, and operates across a temperature range of -55°C to +150°C with a thermal resistance of 4.2°C/W. It is AEC-Q200 compliant and RoHS compliant, with a maximum operating voltage of 250 V and dielectric strength of 2 kV AC. This automotive-grade component is ideal for power supplies, motor drives, test and measurement equipment, and rectifier applications where reliability and thermal performance are critical.