50 Series Wirewound Power Resistors Ohmite 50 Series Wirewound Power Resistors is an economically priced, industrial-grade wirewound power resistor. The 50 Series feature an all-welded construction with a high purity alumina ceramic core and high-quality RoHS grade tinned copper wire instead of copper weld, which produces better thermal characteristics. Ohmright 50 series accompanies Ohmite's wide range of axial leaded products.