| 1. Scope of the coverage： |
| This specification is pertinent to the application of fixed
metal oxide resistors (designated as RS). |
| 2 .Temperature range of the application： |
| -55℃ ～ +155℃。 |
| 3. Type： |
| Two types of fixed metal oxide resistors are
available, one is normal size and the other one is |
| small size. These two types are distinguished by the color
of the coating resin. The color of the |
| resin for the normal size is gray and that for the small
size is pinkish red. |
| 4.Marking and illustration： |
| Two types of designation methods are available for metal
oxide resistors. One is black ink |
| alphanumeric marking and the other one is color code marking.
The criteria of using either one of |
| the marking methods depend on the size of the resistors
and customers request which is listed in |
| the following: |
| alphanumeric marking →1/2W、1W、2W、3W、S1W、S2W、S3W、S5W、S7W
(Fig.1) |
| color code marking →1/4W、S1/2W (Fig.2) (Larger sizes are
available upon request.) |
 (Fig.1) |
 (Fig.2) |
| Illustration of color codes： |
 |
1-st Band
(Sig. digit) |
2-nd Band
(Sig. digit) |
3-rd Band
(Multiplier) |
4-th Band
(Tolerance) |
| Black |
0 |
0 |
1 |
. |
| Brown |
1 |
1 |
10 |
±1% |
| Red |
2 |
2 |
100 |
±2% |
| Orange |
3 |
3 |
1000 |
. |
| Yellow |
4 |
4 |
10000 |
. |
| Green |
5 |
5 |
100000 |
±0.5% |
| Blue |
6 |
6 |
1000000 |
±0.25% |
| Purple |
7 |
7 |
10000000 |
±0.1% |
| Gray |
8 |
8 |
. |
±0.05% |
| White |
9 |
9 |
. |
. |
| Gold |
. |
. |
0.1 |
±5% |
| Silver |
. |
. |
0.01 |
±10% |
|
| |
| 5.Dimension, voltage, resistance range: listed
in the following Table |
| Rated
Power
(W) |
Type |
Resistance
Range
(Ω) |
Higest
Working
Voltage
(V) |
Higest
Overload
Voltage
(V) |
 2 |
| J ( ±5%) |
L |
Dψ |
ι |
dψ |
| 1/4 |
Normal |
0.1～910K |
250 |
500 |
6±0.3 |
2.4±0.1 |
28±2 |
0.6±0.05 |
| 1/2 |
Small |
0.1～910K |
250 |
500 |
6±0.3 |
2.4±0.1 |
28±2 |
0.6±0.05 |
| Normal |
0.1～470K |
250 |
500 |
9±0.5 |
3.0±0.5 |
30±3 |
0.6±0.05 |
| 1
|
Small |
0.1～470K |
350 |
600 |
9±0.5 |
3.0±0.5 |
30±3 |
0.8±0.05 |
| Normal |
0.1～750K |
350 |
700 |
|
4.0±0.5 |
38±3 |
0.8±0.05 |
| 2 |
Small |
0.1～750K |
350 |
700 |
|
4.0±0.5 |
38±3 |
0.8±0.05 |
| Normal |
0.1～330K |
350 |
700 |
|
5.5±0.5 |
38±3 |
0.8±0.05 |
| 3 |
Small |
0.1～330K |
350 |
700 |
|
5.5±0.5 |
38±3 |
0.8±0.05 |
| Normal |
0.1～100K |
500 |
1000 |
|
8.5±0.5 |
38±3 |
0.8±0.05 |
| 5 |
Small |
0.1～100K |
500 |
1000 |
|
8.5±0.5 |
38±3 |
0.8±0.05 |
| Small |
0.1～47K |
500 |
1000 |
For erect H
type resistor (H15、H25) |
| 7 |
Small |
0.1～10K |
500 |
1000 |
For erect F type resistor |
|
| |
| 6.Coating |
 |
| 6.1 The body of the resistor is covered by nonflammable
silicon resin. |
| 6.2 The maximum length of the lead wire covered by the
resin is 2mm. |
| 6.3 The maximum area of the end cap which is not covered
by the resin is half of the diameter of |
| the cap. |
| 6.4 The status of coating condition described by 6.2 and
6.3 are acceptable. |
| |
| 7.Characteristics of electrical performance |
| 7.1 Rated power |
| The rated power indicates the maximum power the resistor
can endure continuously when the |
| ambient temperature is equal to or lower than 70℃. When
the ambient temperature is higher than |
| 70℃, the rated power of the resistor is determined by the
derating curve described in the following |
| figure. |
| |
|
| 7.2 Rated voltage |
| The rated voltage of a resistor is either a continuous
DC voltage or an AC rms voltage which can be |
| calculated by the following formula. If the calculated
rated voltage is higher than the highest |
| working voltage then the highest working voltage should
be used as the rated voltage. |
 P: Rated power(W) R: Nominal resistance(Ω)
E: Rated voltage(V) |
| |
| 7.3 Insulation resistance (Ref. JIS C5202 5.6) |
| Equipment: Insulation resistance tester |
| The body of the resistor is wrapped around by the aluminum
foil without extending beyond the |
| resistor body. Clap one electrode on the aluminum foil
and the other electrode on the lead wire. |
| Apply 100V or 500V from the tester for 1 min. and the measured
resistance value should be larger |
| than 1,000MW. |
| |
| 7.4 Dielectric strength (Ref. JIS C5202 5.7) |
| Equipment: Dielectric strength tester |
| The body of the resistor is wrapped around by the aluminum
foil without extending beyond the |
| resistor body. Clap one electrode on the aluminum foil
and the other electrode on the lead wire. |
| Apply following voltage from the tester to the resistor
for 1 min. No flash-over, burning or |
| breakdown should be observed. |
| Type |
1/4W |
1/2W |
1W |
2W |
3W |
5W |
7W |
| Normal |
250V |
250V |
350V |
350V |
500V |
---- |
---- |
| Small |
---- |
250V |
350V |
350V |
350V |
500V |
---- |
| Special (Erect)
|
---- |
---- |
---- |
---- |
---- |
800V |
800V |
|
| |
| 7.5 Short time overload (SOL) (Ref. JIS C5202 5.5) |
| Equipment: S.O.L. tester. |
| Apply 2.5 times of rated voltage to the resistors for 5
seconds. If the applied voltage is larger than |
| the voltage listed in the following table, then the voltage
in the table should be used instead. After |
| the test, the sample should be stabilized at room temperature
for 30 min. before the resistance is |
| measured. The change of the resistance before and after
the test should be: normal size: |
| (1%+0.05Ω); small size: ±(2%+0.1Ω). |
| |
| Type |
1/4W |
1/2W |
1W |
2W |
3W |
5W |
7W |
| Normal |
500V |
500V |
700V |
700V |
1000V |
---- |
---- |
| Small |
---- |
500V |
600V |
700V |
700V |
1000V |
---- |
| Special (Erect) |
---- |
---- |
---- |
---- |
---- |
1000V |
1000V |
|
| |
| 7.6 Intermittent overload (Applicable for nominal resistance
larger than 100Ω) (Ref. JIS C5202 5.8) |
| Equipment: Intermittent Table. |
| Firstly put the resistor to the environment chamber at
55±2℃ and relative humidity at 20% for 24 |
| hours. After that, take the resistor out and stabilize
it at room temperature for 30 min. Measure the |
| resistance before the test. Put the resistor to a horizontal
position and a distance of 50mm from |
each other. Apply 4 times of rated voltage with a cycle
of 1 sec. ON and 25 sec. OFF for 
|
| cycles. After that, take out the resistor and let it rest
at room temperature for 30 min. and then |
| measure the resistance. The acceptable % change of resistance
is: normal size: ±(2%+0.1Ω); |
| small size: ±(5%+0.1Ω). The maximum applied voltage should
not exceed the value listed in the |
| following Table: |
| Type |
1/4W |
1/2W |
1W |
2W |
3W |
5W |
7W |
| Normal |
500V |
500V |
750V |
750V |
1500V |
---- |
---- |
| Small |
---- |
500V |
750V |
750V |
750V |
1500V |
---- |
| Special (Erect) |
---- |
---- |
---- |
---- |
---- |
1500V |
1500V |
|
| |
| 7.7 Flame proof (Ref. JIS C5202 7.12 3.4(2)c) |
| Equipment: AC power supply |
| Apply 2 times, 4 times, 8 times, 16 times and
32 times of rated voltage sequentially. The duration |
| for each voltage application is 1 min.. The resistor
should not demonstrate arcing, burning or melt |
| down except when the applied voltage exceeds 10
times of rated power. Under this circumstance |
| of applied more than 10 times of rated power,
arcing or burning is acceptable but the duration |
| should be less than 5 sec. And the height of flame
should be less than 3.5mm. The maximum |
| applied voltage should not exceed 4 times of the
value listed in the following table: |
| Type |
1/4W |
1/2W |
1W |
2W |
3W |
5W |
7W |
| Normal |
250V |
250V |
350V |
350V |
500V |
---- |
---- |
| Small |
---- |
250V |
350V |
350V |
350V |
500V |
---- |
| Special (Erect) |
---- |
---- |
---- |
---- |
---- |
500V |
500V |
|
| |
| 8.Environmental tests |
| 8.1 Load life test (Endurance with rated load) (Ref. JIS
C5202 7.10) |
| Equipment: High temperature chamber and DC power supply |
| The resistors are put in a fixture where no interference
will be allowed. Put the fixture in a 70±3℃ |
chamber and apply rated voltage with a cycle of
90 min. ON and 30 min. OFF for 
hours. |
| After 240, 480, 720 and 1,000 hours, the resistors are
taken out and stabilize at room temperature |
| for 30 min. and then the resistance is measured. Upon each
step of resistance measurement, the |
| change of the resistance should not exceed ±(5%+0.1Ω) and
the appearance should show no |
| remarkable abnormality and legibility of marking. |
| |
| 8.2 Resistance to cold (Ref. JIS C5202 7.1) |
| Equipment: Constant temperature and humidity chamber |
| Put the resistors to the chamber with -40±2℃, RH=90～95%
for 240±4 hours. Take them out and |
| put them in room temperature for 1～4 hours then measure
the resistance. The acceptable |
| change of resistance should not exceed ±(1%+0.05Ω) and
the appearance should show no |
| remarkable abnormality and legibility of marking. |
| |
| 8.3 Endurance under damp heat and load (Ref. JIS C5202
7.9) |
| Equipment: Constant temperature and humidity chamber, DC
power supply |
| The resistors are put in a fixture where no interference
will be allowed. Put the fixture in a 40±2℃ |
| chamber with RH=90～95% and apply rated voltage with a cycle
of 90 min. ON and 30 min. OFF for |
| hours. Water drops should avoid dripping
on the resistors. After 240 and 1,000 hours, the |
| resistors are taken out and stabilize at room temperature
for 1 hour and then the resistance is |
| measured. Upon each step of measurement, the change of
the resistance should not exceed |
| ±(5%+0.1Ω) and the appearance should show no remarkable
abnormality and legibility of marking. |
| |
| 8.4 Temperature coefficient (TCR) (Ref. JIS C5202 5.2) |
| Equipment: High temperature chamber |
| Measure the resistance at room temperature. Put the resistor
in a chamber with the temperature of |
| RT+100℃ for 30 - 45 min. to stabilize. Measure the resistance
again. Compare the resistance at |
| these two temperatures with the following equation and
the acceptable value is ±350 PPM/℃. |
 |
| R = Resistance at T T = RT + 100℃ Ro = Resistance at To
To =room temperature |
| |
| 8.5 Temperature cycling (Ref. JIS C5202 7.4) |
| Equipment: High temperature chamber, low temperature chamber |
| Measure the resistance before the test. Put the resistor
to -55℃ chamber for 30 min. then take it |
| out at room temperature for 2 to 3 min.. Put the resistor
to +155 ℃chamber for 30 min. then take it |
| out at room temperature for 2 to 3 min. This completes
a cycle. Repeat the cycle 5 times. Put |
| resistors at room temperature for 90 min. and then measure
the resistance. Compare the |
| resistance before and after test. The acceptable change
of resistance is ±(1%+0.05Ω). The |
| appearance should show no remarkable abnormality and legibility
of marking. |
| |
| 8.6 Low temperature storage (Ref. JIS C5202 7.1) |
| Equipment: Low temperature chamber |
| Stabilize the resistor at room temperature for 30 min.
then measure the resistance. Put the |
| resistors into the chamber and gradually lower the temperature
to -55±3℃ and maintain at that |
| temperature for 24+4-0 hours. Gradually raise the temperature
of the chamber to room |
| temperature and then take resistors out and stabilize at
room temperature for 1 to 2 hours. |
| Measure the resistance value. The change of the resistance
before and after the test should be |
| less than ±(1%+0.05Ω). The appearance should show no remarkable
abnormality and legibility of |
| marking. |
| |
| 8.7 Resistance to heat (Ref. JIS C5202 7.2) |
| Equipment: High temperature chamber |
| Measure the resistance at room temperature. Put the resistors
to 200℃ chamber for 2 hours. |
| Take resistors out and stabilize at room temperature for
1 hour. Measure the resistance value. The |
| change of the resistance before and after the test should
be less than ±(2%+0.1Ω). The |
| appearance should show no remarkable abnormality and legibility
of marking. |
| |
| 9.Mechanical performance |
| 9.1 Resistance to soldering heat (Ref. JIS C5202 6.4) |
| Equipment: Solder bath |
| Measure the resistance before the test. Immerse part of
the lead wire which is 4±0.8mm away from |
| the body to the flux for 5 - 10 sec. Take the resistor
out and immerse resistors in the solder bath of |
| 350±10℃ for 3.5±0.5 sec.. Stabilize at room temperature
for 1 hour and then measure the |
| resistance value. Compare the resistance values before
and after the test, The acceptable change |
| is ±(1%+0.05Ω). |
| |
| 9.2 Solderability (Ref. JIS C5202 6.5) |
| Equipment: Solder bath |
| Immerse part of the lead wire which is 4±0.8mm away from
the body to the flux for 5 - 10 sec. Take |
| the resistor out and immerse resistors in the
solder bath of 245±5℃ for 3.5±0.5 sec.. Take the |
| resistor out and inspect the lead wire visually. The acceptable
level is the coverage of the new |
| solder to be 95%. The composition of the solder bath is
99.7% tin and 0.3% Cu. |
| |
| 9.3 Robustness of terminals (Ref. JIS C5202 6.1) |
| 9.3.1 Tensile strength of termination |
| Equipment: Weight gauge |
| Fixed the resistor and apply axially along the lead wire
of 2.5Kg (0.8φ lead wire) or 1.0Kg (0.6φ lead |
| wire) for 30 sec.. The lead wire should not break or detached
from the resistor and the change of |
| the resistance should be less than ±(0.5%+0.05Ω). |
| |
| 9.3.2 Torsional strength |
| Equipment: Torsion tester |
| Bend the terminal 6.4mm away from the body according to
Fig-a to 90 degree with a curvature of |
| 0.75mm～0.80mm. The lead wire should be clamped at a point
of 1.2mm away from the bending |
| point by a fixture which can rotate 360 degree according
to Fig-b. Rotate the resistor 360 degree |
| clockwise and counter clockwise for 1 cycle. The rotation
speed is 360 degree per 5 sec.. Perform |
| 3 cycles for the lead wire diameter of 0.8φ and 1.5 cycles
for that of 0.6φ. The terminal should not |
| break down or detached from the body. The acceptable change
of resistance is ±(0.5%+0.05Ω). |
  |
| |
