The rated power of a resistor means the max allowable power applied to the resistor in continual operation at specified ambient temperature. Usually, the type of resistor as a load is determined on the basis of the power consumption of the resistor. For instance, a square-typed chip resistor provide max power of 1W most of the time. But when the ambient temperature exceeds 70°C, a decrease in power supply to the load is indispensible.
The resistance range refers to the available range of resistors that can replace other manufacturers' series or types of resistors as alternative ones. Resistors in a resistance range 1Ω to 1MΩ are usually available. Sometimes a resistor with a resistance of less than1Ω or more than 1MΩ is required.
The resistance tolerance of a resistor refers to the max allowed deviation of the nominal resistance of the resistor. This value is expressed by the code F, G, J, K, or M, which respectively refers to a allowed tolerance of ±1%, ±2%,±5%, ±10%, and ±20%.
Nominal resistance，expressed by E-series nominal standard resistance values, is established by the IEC. An E-series nominal standard resistance value is determined on the basis of an initial value of 1, a common radio of 10, and the series number n (6, 12, 24, and so forth). The rules are set to regulate the tolerance of each resistance value.
The rated voltage of a resistor means the max root-mean-square value of AC or the max value of DC that can be continuously imposed to the resistor at a specified ambient temperature. If the rated voltage does not exceed the max working voltage of the resistor, the rated voltage value can calculated by the rated power and nominal resistance. Usually the withstand voltage of a resistor refers to this value.
Resistors' features vary depending on the materials, structures and technologies. Choosing a resistor of appropriate resistance, power, tolerance enable the effectiveness of the applications.
