scope:

This specification covers the general requirements for power type, wire-wound, fixed resistors for use in electrical, electronic, communications, and associated equipment. Included are general purpose styles of 5-percent initial resistance tolerance with power ratings ranging from 3 to 240 watts at 25°C, derated to 0 power at 350°C (characteristic V) and precision axial lead types of .1, .5, and 1-percent initial resistance tolerances with power ratings ranging from 1 to 10 watts at 25°C, derated to 0 power at 275°C (characteristic U).