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6. ENVIRONMENTAL CHARACTERISTICS
(1) Short Time Over Load Test
At 2.5 times of the rated voltage applied for 5 seconds, the resistor should be free from defects after the
resistor is released from load for about 30 minutes
Short Time Overload Voltage =
Value ResistanceRatingPower *5.2
The change of the resistance value should be within ± 2.0 % + 0.05Ω
(2) Voltage Proof
The resistor shall be clamped in the trough of a 90° metal V Block. Apply the insulation voltage of 1000V
between the terminals connected together with the block for about 60 seconds.
The resistor shall be able to withstand without breakdown or flashover.
(3) Temperature Coefficient Test
Test of resistors above room temperature 100°C ± 2°C ( Testing Temperature 115°C to 130°C ) at the
constant temperature silicon plate for over 5 minutes. Then measure the resistance value.
The Temperature Coefficient is calculated by the following equation and its value should be within the
range of requested.
6
00
0
10
tt
1
R
RR
tCoefficieneTemperatursistorRe
R ＝ Resistance value under the testing temperature
R0 ＝ Resistance value at the room temperature
t ＝ The testing temperature
t
o
＝ Room temperature
(4) Insulation Resistance
Apply "measuring voltage" between protective coating and termination for 1 min.,then measure. The
measuring voltage shall be either 100V±15V d.c. for resistors with an insulation voltage lower than 500V
or 500V±50V d.c. for resistors with an insulatin voltage equal to or greater than 500V.
The test resistance should be high than 1,000M ohm.
(5) Solderability
Immerse the specimen into the solder pot at 235 ± 5 °C for 3 ± 0.5 seconds.
At least 90% solder coverage on the termination.
(6) Solvent Resistance of Marking
The specimen into the appropriate solvent of IPA condition of ultrasonic machine for 5± 0.5 minutes.
The specimen is no deterioration of coatings and color code.
(7) Robustness of Terminations
Direct Load – Resistors shall be held by one terminal and the load shall be gradually applied in the
direction of the longitudinal axis of the resistor unit the applied load reached the requirement.
The load shall be held for 10 seconds. The load of weight shall be ≧ 2.5 kg ( 24.5N ).
