ANTI-PULSE NON-INDUCTIVE RESISTORS
1. Applicable Scope:
This standard specification is for use in consumer electronics, computers, telecommunications, control
instruments...etc.
2. Part Number:
It is composed by Type, Rated Wattage, Nominal Resistance, Tolerance and Package/Terminal Form
. e.g.
NRSN
1W
Type
Rated Wattage
1KΩ
Nominal Resistance
J
T/B
Tolerance Package/Terminal Form
2.1 Type :
Anti-Pulse Non-Inductive Resistors are called "NRSN" &"NRSS"(small size).
2.2 Rated Wattage:
Shown by "W", such as 1/4W, 1/2W, 1W, 2W, 3W.
2.3 Nominal Resistance:
Ω, KΩ are its unit, which be in accordance with JIS-C6409 article 6 (EIA RS-196A) series.
2.4 Tolerance:
It is measured by Bridge-method at room temperature and expressed by a capital letter.
G＝±2% , J＝±5% .
2.5 Package/Terminal Form:
T/R＝tape & reel ; T/B＝tape in box; Nil＝Bulk; MG form, F forms.
Remark :NRSN & NRSS Series Resistors are RoHS Compliant.
3. Rated Power:
Rated power is the value of Max load voltage specified at the ambient temperature of 70℃, and shall meet
the functions of electrical and mechanical performance. When the ambient temperature surpasses above
mentioned temperature, the value declines as per following DERATING CURVE.
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ANTI-PULSE NON-INDUCTIVE RESISTORS
3.1 Rated Voltage:
It is calculated through the following formula:
E
=
P
*
R
where E: rated voltage (V)
P: rated power (W)
R: nominal resistance value (Ω)
However, in case the voltage calculated exceeds the maximum load voltage, such the maximum load
voltage shall be regarded as its rated voltage, means whichever less.
4. Dimension and structure:
4.1 Dimension:
Unit: mm
TYPE
D±1
NRSS
1/2W
NRSN
1/4W
1/2W
1W
2W
3W
1W
2W
2.6±0.5
3
3.5
4.5
5
6.8
9
9
11
15
28
28
28
28
28
0.6
0.65
0.65
0.8
0.8
0.22Ω~200KΩ
0.22Ω~200KΩ
0.22Ω~200KΩ
0.22Ω~200KΩ
0.22Ω~200KΩ
250V
300V
350V
350V
350V
400V
400V
600V
600V
600V
L±1
H±3
d±0.1
Resistance Range
Max Working
Voltage
Max Overload
Voltage
Notes:Too low or too high ohmic values can be supplied only case by case.
4.2 STRUCTURE:
4.2.1 Ceramic Rod:
It is made of Forsterite imported from Japan.
4.2.2 Terminal:
Terminal is to be firmly connected with resistors element, both electrically and mechanically,
and allow easy soldering.
4.2.3 Coating:
Coating is done by light gray flameproof paint for NRSN type and dark gray flameproof for
NRSS (resistant to 800℃) which is solid enough to be free from looseness, crack and easy
breakage. It is also resistant to cleaning and industrial solvents, and the paint shall be limited
within 2mm of lead wires from resistor body.
4.2.4 Marking: Marking is made on resistors surface, by five color coding; 1st, 2nd, 3rd: nominal
resistance, 4th: tolerance, 5th: white for Non-Inductive resistors.
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ANTI-PULSE NON-INDUCTIVE RESISTORS
5. Operating Temperature Range: -55℃½155℃
6. Mechanical Performance:
6.1 Terminal tensile:
To fix the resistor body, a static load of 2.5kgs. (under 1/2W:1kg.)is to be gradually applied into the
terminal for 10 seconds without causing any looseness and fall.
6.2 Twist withstand:
To bend the lead wire at the point of about 6mm from resistor body to 90°, then catch the wire at 1.2
±0.4mm apart from the bent point end and turn it (clockwise) by 360 degrees perpendicular to the
resistor axis at speed of 5 seconds per turn, and do the same counterclockwise again which constitute
a whole turn. Repeat the turn 2 times without causing any break and looseness.
7. Electrical Performance:
7.1 Resistance Temperature Coefficient:
It shall be within ±300ppm/℃.
T.C (ppm/℃) =［(R2－R1)÷R1½×［1÷(T2－T1)½×10
6
where
R1: resistance value at reference temperature
R2: resistance value at test temp.
T1: reference temp. (usu. 25℃)
T2: test temp. (about 75℃)
7.2 Short Time Over Load:
When the resistors are applied 2.5 times as much as rated voltage for 5 seconds continuously, it
shows no evidence of arc, flame...etc. Removing the voltage and place the resistors to the normal
condition for 30 minutes, the resistance value change rate between pre-and-post test shall be within
±1%(NRSS＝±2%).
7.3 Insulation Character :
Resistors are located in a V-shaped metal trough. Using the DC 500V megger instrument 2 poles to
clutch either side of lead wires and metal trough, measuring the Insulation Resistance which shall be
over 1000MΩ.
7.4 Voltage Withstanding:
Resistors are located in a V-shaped metal trough. Applying Max Working Voltage for one minute
and should find no physical damage to the resistors, such as arc, char ...etc.
7.5 Load Life:
The resistors arrayed are sent into the 70℃ oven, applying rated voltage at the cycle of 1.5 hours
ON, 0.5 hour OFF for 1000
+48
hours in total. Then, after removing the voltage, take the resistors out of
-0
the oven and left under normal temp. for one hour cooling. The resistance value change rate between
pre-and-post test shall be within ±5%.
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ANTI-PULSE NON-INDUCTIVE RESISTORS
7.6 Moisture-proof Load Life:
The resistors arrayed are placed into a constant temp./humidity oven at the temp. of 40 ±2℃ and the
humidity of 90½95%, then rated power is applied for 1.5 hours and cut off for 0.5 hour. The similar
cycle will be repeated for 500
+24
hours in total (including cut-off time). Then remove the voltage,
-0
taking the resistors out of the oven and leaving them at room temp. for one hour. The resistance value
change rate between pre-and-post test shall be within ±5%. There also shall be no evidence of
remarkable change on appearance, and the marking shall not be illegible.
7.7 Solder-ability:
The leads with flux are dipped in a melted solder of 235 ±5℃ for 2 seconds, more than 95% of the
circumference of the lead wires shall be covered with solder.
7.8 Resistance to Soldering Heat:
Two leads are together dipped in a melted solder of 270 ±5℃ for 10 ±1 seconds, or 350 ±10℃ for
3.5 ±0.5 seconds, Then remove the resistors and leaving them at room temp. for one hour. The
resistance value change rate between pre-and-post test shall be within ±1%.
7.9 Nonflammability:
The resistors are applied the power of 16 times the rated wattage for 5 min. and shall not get flame.
7.10 Inductance:
It shall be less than 1μH.
8. Others:
8.1 MG Form:
Unit: mm
NRSS
1W
2W
3W
1W
2W
NRSN
D±1
3.5
4.5
5
L±1
9
11
15
P
15±1.5
15±1.5
20±2
H
7±1
7±1
10±2
h±1
4.5
4.5
4.5
A±0.02
0.23
0.25
0.25
B±0.05
0.8
1
1
C±0.2
1.2
1.4
1.4
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