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Glossary

Power Rating
The maximum value of power that can be continuously loaded at the rated ambient temperature.


Rated Voltage
The maximum value of DC voltage or AC voltage (commercial frequency effective value) that can be continuously applied to a resistor at the rated ambient temperature. Rated voltage is calculated from the following formula.
Rated Voltage(V)=√Rated Power(W) x Nominal Resistance(Ω)
However, it shall not exceed the maximum working voltage.


Critical Resistance Value
The maximum nominal resistance value at which the rated power can be loaded without exceeding the maximum working voltage. For the critical resistance value, the rated voltage and the maximum working voltage are equal.


Maximum Working Voltage
The maximum value of DC voltage or AC voltage (commercial frequency effective value) that can be continuously applied to a resistor or resistance element. However, if it is no more than the critical resistance value, the maximum value of the voltage that can be applied is the rated voltage.

Maximum Overload Voltage
Maximum value of voltage that can be applied for 5 seconds in the overload test (JIS C 5201-1 4.13). Normally, the applied voltage in the overload test is 2.5 times the rated voltage. However, it shall not exceed the maximum overload voltage.


Rated Ambient Temperature
The maximum ambient temperature of a resistor that can be used continuously with the specified rated load (power) applied.


Derating Curve
A curve showing the relationship between the ambient temperature and the maximum value of power that can be continuously loaded at that temperature.


Temperature Coefficient of Resistance (T.C.R.)
The rate of change of resistance value per 1 ℃ between specified temperatures within the operating temperature range of the resistor. It is calculated by the following formula.
T.C.R. (x 10-6/K)=(R-R0)/R0 x 1/(T-T0)×106
R: Measured resistance (Ω) at T℃
R0: Measured resistance (Ω) at T0℃
T: Measured test temperature (℃)
T0: Measured base temperature (℃)

Resistance to pulse
In case of the circuits where excessive (single and repeated) overload like pulse or surge etc. are applied to, if voltage/current/power over than rating is applied, there are fears of the degradation of performance (disconnection, resistance change, etc.) and decline of reliability. Confirm sufficiently with the actual circuit considering the dispersion of constants of other parts. Please let us know in advance if you need the data of anti-pulse characteristics.