| 1. Scope of the coverage： |
| This specification is pertinent to the application of fixed
metal film resistors (designated as RN). |
| 2 .Temperature range of the application： |
| -55℃ ～ +155℃。 |
| 3.Type： |
| Two types of fixed metal film resistors are available,
one is normal size and the other one is small |
| size. Except the color of S1/2W which is deep blue epoxy
resin, the rest of the epoxy resin color is |
| light blue. |
| |
| 4.Marking and illustration： |
| The marking method for the fixed metal film resistor is
color code which is shown in Fig.1. |
| |
| |
| |
| Illustration of color codes： |
| 5%
Designation |
1-st Band
(Sig. digit) |
2-nd Band
(Sig. digit) |
|
3-rd Band
(Multiplier) |
4-th Band
(Tolerance) |
| |
1-st Band
(Sig. digit) |
2-nd Band
(Sig. digit) |
3-rd Band
(Sig. digit) |
4-th Band
(Multiplier) |
5-th Band
(Tolerance) |
| Black |
0 |
0 |
0 |
1 |
. |
| Brown |
1 |
1 |
1 |
10 |
±1%(F) |
| Red |
2 |
2 |
2 |
100 |
±2%(G) |
| Orange |
3 |
3 |
3 |
1000 |
. |
| Yellow |
4 |
4 |
4 |
10000 |
. |
| Green |
5 |
5 |
5 |
100000 |
±0.5%(D) |
| Blue |
6 |
6 |
6 |
1000000 |
±0.25%(C) |
| Purple |
7 |
7 |
7 |
10000000 |
±0.1%(B) |
| Gray |
8 |
8 |
8 |
. |
±0.05%(A) |
| White |
9 |
9 |
9 |
. |
. |
| Gold |
. |
. |
. |
0.1 |
±5%(J) |
| Silver |
. |
. |
. |
0.01 |
±10%(K) |
|
| |
| 5.Dimension, voltage, resistance range: listed in
the following Table |
| Type |
Rated
Power
(W) |
Resistance range (Ω) |
Highest working
(V) |
Highest Overload
(V) |
 2 |
| J ( ±5%) |
L |
Dψ |
ι |
dψ |
| normal |
1/8W |
10～1M |
200 |
400 |
3.5±0.5 |
1.7±0.3 |
27±3 |
0.45±0.05 |
| normal |
1/6W |
10～1M |
200 |
400 |
3.5±0.5 |
1.7±0.3 |
27±3 |
0.45±0.05 |
| small |
S1/4W |
10～2.2M |
200 |
400 |
3.5±0.5 |
1.7±0.3 |
27±3 |
0.45±0.05 |
| normal |
1/4W |
10～2.2M |
200 |
500 |
6.0±0.5 |
2.3±0.3 |
27±3 |
0.52±0.05 |
| small |
S1/2W |
10～5.1M |
250 |
500 |
6.0±0.5 |
2.3±0.3 |
27±3 |
0.52±0.05 |
|
normal |
1/2W |
10～5.1M |
350 |
700 |
9.0±1.0 |
3.2±0.5 |
27±3 |
0.56±0.05 |
|
| |
| 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 0.5mm. |
| 6.3 The maximum area of the end cap which is not covered
by the resin is half of the diameter of |
| 6.3 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 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. |
| Rated power |
1/8W |
1/6W |
S1/4W |
1/4W |
S1/2W |
1/2W |
| Voltage |
300V |
300V |
300V |
500V |
500V |
500V |
|
| |
| 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:±(0.5%+0.05Ω). |
| Rated Power |
1/8W |
1/6W |
S1/4W |
1/4W |
S1/2W |
1/2W |
| Highest Voltage |
400V |
400V |
400V |
500V |
500V |
700V |
|
| |
| 7.6 Intermittent overload (Applicable for nominal resistance
larger than 100Ω) (Ref. JIS C5202 5.8) |
| Equipment: Intermittent tester |
| Put the resistor to a test fixture in a horizontal
position, apply Y times of rated voltage for 1 sec. ON |
and 25 sec. OFF for 
times. After the test, take the sample out and stabilize at
room |
| temperature for 30 min. then measure its resistance. The
acceptable change of resistance before |
| and after the test is ±(1%+0.05Ω). The applied voltage
should not exceed the value listed in the |
| following table. |
| Rated power |
1/8W |
1/6W |
S1/4W |
1/4W |
S1/2W |
1/2W |
| Highest Voltage |
400V |
400V |
400V |
500V |
500V |
700V |
| Times (Y) |
3 |
3 |
3 |
4 |
4 |
4 |
|
| |
| 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 ±(1%+0.05Ω)
and the appearance should show no |
| remarkable abnormality and legibility of marking. |
| |
| 8.2 Resistance to damp heat (Ref. To JIS C5202 7.2) |
| Equipment: Constant temperature and humidity chamber |
| The resistors are put in a 40±2℃ chamber with RH=90～95%
for 240±4 hours. After the test, take |
| the resistors out and stabilize in room temperature for
1 - 4 hour. 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 |
| ±(1%+0.05Ω) and the appearance should show no remarkable
abnormality and legibility of |
| marking. |
| |
| 8.4 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. |
| |
| 8.5 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: ±100PPM/℃。 |
 |
| R = Resistance at T T = RT + 100℃ Ro = Resistance at To
To =room temperature |
| |
| 8.6 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. |
| |
| 8.7 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 
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. |
| (Remove any water condensation on the resistor body during
the test) |
| |
| 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 6±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 ±(0.5%+0.05Ω). |
| |
| 9.2 Solderability (Ref. JIS C5202 6.5) |
| Equipment: Solder bath |
| Immerse part of the lead wire which is 3±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 0.5kg (0.45φlead wire)，1.0kg (0.52φ, |
| 0.60φlead 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 |
| 0.45φ, 0.52φ lead wire 1 cycle, 0.60φ 1.5 cycles.
The terminal should not break down or detached |
| from the body. The acceptable change of resistance is ±(0.5%+0.05Ω). |
  |
| |
