Resistors have a specified power rating, based on continuous full-load operationat an ambient temperature. This power rating is dependent upon the ability of re-sistors to meet the pecifiedload-life requirements.
For resistors operated at an ambient temperature in excess of the specified am-bient temperature, the load should be derated in accordance with the specifiedcurve Resistors have a rated DC or an approximate sine-wave rms ACcontinuous working voltage at commercial-line frequency and wave form corresponding to the power rating, as determined from E=SQRT(P*R) (E=Rated DC or rms AC continus working voltage. P=Power rating, R=Nominal resistance). In that case shall the rated DC or rms AC continuous working voltage be greater then the applicable maximum value specified.

As a component part for electronic and electrical equipment and appliances, the resistors in their characteristics and performances in service are affected from va-rious deleterious elements and conditions surrounding its operation, appliance-inherent as well as environment and physical.
These deleterious factors include humdity, salt fog, altitude. temperature, termalshock, sand and dust, external flame vibration, impack shock, acceleration, solu-ble agent, intermittent and momentary electrical overload, current fluctuation and so on. These factors, individually or in combined, tend to effect the resistor perfomance.

Each resistor with its own rating in wattage, working voltage, max. voltage, tempe-rature and resistance tolerance has corresponding design and construction, by utilizing appropriate materials and controlled manufacturing processes for its in-tended applications, and the quality and reliabilityare reassured, prior to deli-very,through testing and examining under the conditions simulating actual operationin the field.

When testing our resistors to determine such characteristics as overload, the over-potential to be applied should not exceed 2.5*(E=SQRT(P*R)) or max. voltage specifiedwhichever less.

When selecting resistors, It is recommanded to evaluate basic electrical ratings,characteristics

and dimensions as shown on this catalog in light of the requireme-nts given by the application and specific circuit in questions. Good performanceof resistor should be backed up by user's suitable selection especially for follo-wing case.

A. Circuit involving high voltage. Proper spacing and arrangement between resis-tors and other neighboring components are important in view of generators heat and subsequent humidization.

B. Circuit involving high current flow. Resistors in parallel could be utilized, but with care.

C. Circuit involving high frequency, pulse, high peak, high frequency resonance.Sufficient value in power rating is to be provided.

D. Operation condition involving intermittent or momentary overload. Sufficient value in power rating is to be provided.

E. Application requiring strict safety standards. Flame-proof type resistor can be of help.