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Carbon Film Resistors (RD)
Fusible Film Resistors (RF)
Cement Resistors (RG)
Metal Glaze Resistors (RM)
Metal Film Resistors (RN)
Metal Oxide Resistors (RS)
Wire Wound Resistors (RW)
Insulated 0Ω Resistors (RZ)
Metal Plate Resistors (MPC)
Anti-burst Fusible Resistor
(RFB)


 

Metal Oxide Resistors (RS)


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
ι
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).
  
 

 

 

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