| 1. Scope of the coverage¡G |
| ¡@This specification is pertinent to the application
of fusible film type resistors( designated as RF ) |
| 2 .Temperature range of the application¡G |
| ¡@-40¢J ¡ã +155¢J¡C |
| 3. Type¡G |
| ¡@Two types of fusible 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¡G |
| ¡@Two types of designation methods are available for
fusible 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¡B1W¡B2W¡BS1W ¡BS2W¡BS3W (Fig.1) |
| ¡@color code marking ¡÷1/6W¡B1/4W¡B1/3W¡BS1/4W¡BS1/2W (Fig.2) |
¡@ |
| ¡@Illustration of color codes¡G |
|
|
1-st Band
(Sig. digit)
|
2-nd Band
(Sig. digit)
|
3-rd Band
(Multiplier)
|
4-th Band
(Tolerance)
|
5-th Band
(Wattage)
|
|
Black
|
0
|
0
|
1
|
.
|
1/4W
|
|
Brown
|
1
|
1
|
10
|
¡Ó1%
|
. |
|
Red
|
2
|
2
|
100
|
¡Ó2%
|
.
|
|
Orange
|
3
|
3
|
1000
|
.
|
.
|
|
Yellow
|
4
|
4
|
10000
|
.
|
.
|
|
Green
|
5
|
5
|
100000
|
¡Ó0.5%
|
.
|
|
Blue
|
6
|
6
|
1000000
|
¡Ó0.25%
|
.
|
|
Purple
|
7
|
7
|
10000000
|
¡Ó0.1%
|
.
|
|
Gray
|
8
|
8
|
.
|
¡Ó0.05%
|
.
|
|
White
|
9
|
9
|
.
|
.
|
1/6W¡B1/3W
|
|
Gold
|
.
|
.
|
0.1
|
¡Ó5%
|
. |
|
Silver
|
.
|
.
|
0.01
|
¡Ó10%
|
S1/4W¡BS1/2W
|
|
| |
| 5.Dimension, voltage, resistance range: listed
in the following table |
|
Rated power
( W )
|
Resistance
Range (£[)
|
Highest working
(V)
|
Highest Overload (V)
|
 2 |
|
J ( ¡Ó5%)
|
L
|
D£r
|
£d
|
d£r
|
|
1/6¡BS1/4
|
0.1¡ã1K
|
100
|
150
|
3.5¡Ó0.5
|
1.7¡Ó0.3
|
27¡Ó3
|
0.45¡Ó0.05
|
|
1/4¡B1/3
|
0.1¡ã15K
|
250
|
300
|
6¡Ó0.3
|
2.4¡Ó0.1
|
28¡Ó2
|
0.6¡Ó0.05
|
|
S 1/2
|
0.1¡ã33K
|
250
|
300
|
6¡Ó0.3
|
2.4¡Ó0.1
|
28¡Ó2
|
0.6¡Ó0.05
|
|
S 1
|
0.1¡ã33K
|
250
|
300
|
9¡Ó0.5
|
3.0¡Ó0.5
|
30¡Ó3
|
0.8¡Ó0.05
|
|
1/2
|
0.1¡ã4.7K
|
250
|
300
|
9¡Ó0.5
|
3.0¡Ó0.5
|
30¡Ó3
|
0.6¡Ó0.05
|
|
1¡BS2
|
0.1¡ã4.7K
|
350
|
500
|
|
4.0¡Ó0.5
|
38¡Ó3
|
0.8¡Ó0.05
|
|
2¡BS3
|
0.1¡ã4.7K
|
350
|
500
|
|
5.5¡Ó0.5
|
38¡Ó3
|
0.8¡Ó0.05
|
|
| |
| 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 2mm. |
| ¡@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¢J.
When the ambient temperature is higher than |
| ¡@70¢J, 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(£[), E: Rated voltage(V) |
| |
| ¡@7.3 Insulation resistance (Ref. JIS C5202
5.6) |
| ¡@Equipment : Insulation resistance tester |
| ¡@The body of the resistor is wrapped 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 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 (W)
|
1/6¡BS1/4
|
1/4¡B1/3¡BS1/2¡B1/2¡BS1
|
1¡B2¡BS2¡BS3
|
|
Voltage (V)
|
200V
|
250V
|
300V
|
|
| |
| ¡@7.5 Short time overload (SOL) (Ref. JIS C5202 5.5) |
| ¡@Equipment: S.O.L. tester. |
| ¡@Apply 2 times of rated voltage to the resistors for
5 seconds. 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: ¡Ó(2%+0.1£[).
|
| |
| ¡@7.6 Flame proof (Ref. to 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 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: |
|
Rated power (W)
|
1/6¡BS1/4
|
1/4¡B1/3¡BS1/2¡B1/2¡BS1
|
1¡B2¡BS2¡BS3
|
|
Highest voltage (V)
|
200V
|
250V
|
300V
|
|
| |
| ¡@7.7 Fusing characteristics |
| ¡@7.7 (residual
resistance after the test is more than 100 times of
the original value) |
|
Type
|
Range
|
|
|
|
|
Fusing Time
|
|
RFU1/6W¡BRFS1/4W
|
0.10~1K£[
|
0.10~0.18£[
|
0.2~0.47£[
|
0.51~1K£[
|
------
|
¡Ø60sec
|
|
RFU1/4W¡BRFU1/3W
|
0.10~15K£[
|
0.10~0.22£[
|
------
|
0.24~9.1£[
|
1.0~15K£[
|
¡Ø60sec
|
|
RFS1/2W
|
0.10~33K£[
|
------
|
------
|
0.10~1.0£[
|
1.1~33K£[
|
¡Ø60sec
|
|
RFS1W
|
0.10~33K£[
|
------
|
------
|
0.10~1.0£[
|
1.1~33K£[
|
¡Ø60sec
|
|
RFU1/2W
|
0.10~4.7K£[
|
0.10~0.33£[
|
0.47~0.91£[
|
1.0~9.1£[
|
1.0~4.7K£[
|
¡Ø60sec
|
|
RFU1W¡BRFS2W
|
0.10~4.7K£[
|
------
|
------
|
0.10~1.0£[
|
1.1~4.7K£[
|
¡Ø60sec
|
|
RFU2W¡BRFS3W
|
0.10~4.7K£[
|
------
|
------
|
0.10~1.0£[
|
1.1~4.7K£[
|
¡Ø60sec
|
|
| |
| 8.Environmental tests |
| ¡@8.1 Load life test (Endurance with rated load) (Ref.
To 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¡Ó3¢J |
¡@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 measurement, the change of |
| ¡@the resistance should not exceed ¡Ó(5%+0.1£[) 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¡Ó2¢J chamber with RH=90¡ã95%
for 240¡Ó4 hours. After the test, take |
| ¡@the resistors out and stabilize in room temperature
for 1 - 4 hour. Measure the resistane. The |
| ¡@acceptable change of resistance should not exceed
¡Ó(2%+0.1£[) and the appearance should show |
| ¡@no remarkable abnormality and legibility of marking. |
| |
| ¡@8.3 Endurance under damp heat and load ()Ref. To
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¡Ó2¢J |
| ¡@chamber with RH=90¡ã95% 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 |
| ¡@¡Ó(5%+0.1£[) and the appearance should show no remarkable
abnormality and legibility of marking. |
| |
| ¡@8.4 Temperature coefficient (TCR) (Ref. To 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¢J for 30 - 45 min. to become stabilized.
Measure the resistance again. Compare the |
| ¡@resistance at these two temperatures with the following
equation and the acceptable value is ¡Ó350 |
| ¡@PPM/¢J. |
¡@ |
| ¡@R = Resistance at T ¡@T = RT + 100¢J¡@Ro = Resistance
at To¡@To =room temperature |
| |
| ¡@8.5 Temperature cycling (Ref. To JIS C5202 7.4) |
| ¡@Equipment: High temperature chamber, low temperature
chamber |
| ¡@Measure the resistance before the test. Put the resistors
to -55¢J chamber for 30 min. then take it |
| ¡@out at room temperature for 2 to 3 min.. Put the
resistor to +155 ¢Jchamber for 30 min. then take it |
| ¡@out at room temperature for 2 to 3 min. This complete
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 ¡Ó(1%+0.1£[). The |
| ¡@appearance should show no remarkable abnormality
and legibility of marking. |
| |
| 9.Mechanical performance |
| ¡@9.1 Resistance to soldering heat (Ref. To JIS C5202
6.4) |
| ¡@Equipment: Solder bath |
| ¡@Measure the resistance before the test. Immerse part
of the lead wire which is 4¡Ó0.8mm away from |
| ¡@the body to the flux for 5 - 10 sec. Take the resistor
out and immerse resistors in the solder bath of |
| ¡@350¡Ó10¢J for 3.5¡Ó0.5 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 ¡Ó(1%+0.1£[). |
| |
| ¡@9.2 Solderability (Ref. To JIS C5202 6.5) |
| ¡@Equipment: Solder bath |
| ¡@Immerse part of the lead wire which is 4¡Ó0.8mm away
from the body to the flux for 5 - 10 sec. Take |
| ¡@the resistor out and immerse resistors
in the solder bath of 245¡Ó5¢J for 3.5¡Ó0.5 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. To JIS C5202 6.2) |
| ¡@9.3.1 Tensile strength of termination |
| ¡@Equipment: Weight gauge |
| ¡@Fixed the resistor and apply axially along the lead
wire of 2.5Kg (0.8£p lead wire) or 1.0Kg (0.6£p 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 ¡Ó(0.5%+0.1£[).
For the destructive test, the lead wire of |
| ¡@0.6£pshoul dbe able to withhold 5Kg, that of 0.8£pshopuld
be bale to withhold 10Kg. |
| |
| ¡@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¡ã0.80mm. 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 0.8£p and 1.5
cycles for that of 0.6£p. The terminal should not |
| ¡@break down or detached from the body. The acceptable
change of resistance is ¡Ó(0.5%+0.1£[). |
| |
¡@ ¡@¡@¡@ |
| |
