Semi-Precision Power
Resistors
Semi-Precision Resistor
Wirewound Power
Semi-Precision Non-Inductive
Wirewound Resistor
AS Series
Power Wirewound Resistors
AS Series
Welwyn Components
Welwyn Components
•
0.25 to 10 watts
•
Tolerance down to ±0.5%
•
0.25 to
NAS Series
10 watts
ohms
•
0.1 ohm to 175K
•
Tolerance down to ±0.5%
0.25 to 10 watts
•
Resistance wire TCR ±20 ppm/°C
•
0.1 ohm to 175K
±0.5%
Tolerance down to
ohms
•
Resistance wire TCR ±20 ppm/°C
0.1 ohm to 51K ohms
Resistance wire TCR ±20 ppm/°C
Non-inductive windings
Pb-free option is RoHS compliant
Electrical Data
Electrical Data
Type
NAS-
1
/
4
NAS-
1
/
2
NAS-1
NAS-1C
NAS-2
NAS-2B
NAS-2C
NAS-3
NAS-5
NAS-7
NAS-10
All Pb-free parts comply with EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3)
AS Standard Range
(ohms)
Min.
Max.
4K0
0R2
Value Min.
6K0
0R24
0R1
R05
0R1
0R1
0R1
0R1
0R1
0R1
0R1
1R0
1R0
0R1
10R
0R5
0R5
0R2
0R5
0R8
1R0
0R3
7K5
2K0
20K
33K
18K
30K
60K
90K
150K
NAS Non-inductive
Range (ohms)
Min.
1R0
Value Max
1R0
0R1
500R
10R
3K0
0R5
3K8
0R5
1K0
0R2
10K
0R5
12K
0R8
7K5
1R0
15K
0R3
30K
45K
51K
Available Tolerance (%)
≥1R0
Equivalent
Power Rating
MIL-R-26
(watts)
Type
Style
125°C
25°C
Power Rating
Equivalent
(N)AS-
1
/
4
1
0.25
(watts)
MIL-R-26
RW81
1
/
2
(N)AS-
1
0.5
Style
125°C
25°C
(N)AS-1
1
RW70U0.25
12
RW81
(N)AS-1C
1
12
0.5
(N)AS-2
RW70U
(N)AS-2B
(N)AS-2C
RW79U
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
RW74U
RW79U 1
1
2
3
RW74U 2
3
RW78U 5
7
2
3
2
3
5
7
10
23
24
33
45
37
59
14
7
9
14
<1R0
Max.
Available Tolerance (%)
500R
3K0
<1R0
3K8
1K0
10K
12K
7K5
3,
15K 5
30K
45K
51K
3, 5
0.5, 1, 3, 5
≥1R0
0.5, 1, 3, 5
10
RW78U
Physical Data
Dimensions Inches (mm)
B (max)
Physical Data
(0.81)
Type
A ±0.032
(N)AS-
1
/
4
0.250(6.4)
Dimensions Inches (mm)
(N)AS-
1
/
2
(0.81)
0.312(7.9)
Type
B (max)
A ±0.032
NAS-
1
/
4
NAS-
1
/
2
NAS-1
NAS-1C
NAS-2
NAS-2B
NAS-2C
NAS-3
NAS-5
NAS-7
NAS-10
C (max)
D (nom)
0.020 (0.5)
E (min)
1.50 (38.1)
0.094 (2.4) 0.312 (7.9)
0.094(max) 0.375 (9.5) 0.020 (0.5) 1.50 (38.1)
E (min)
D (nom)
C (2.4)
(N)AS-1
0.312 (7.9) 0.020 (0.5) 1.50 (38.1)
0.094
0.250(6.4) 0.367(9.3) (2.4) 0.125 (3.2) 0.429 (10.9) 0.020 (0.5) 1.50 (38.1)
(N)AS-1C
0.256(6.5) (2.4) 0.115 (2.9) 0.303 (7.7) 0.025 (0.64) 1.50 (38.1)
0.375 (9.5) 0.020 (0.5) 1.50 (38.1)
0.094
0.312(7.9)
(N)AS-2
0.429 (10.9) 0.020 (0.5) 1.50 (38.1)
0.125
0.367(9.3) 0.480(12.2)(3.2) 0.250 (6.3) 0.600 (15.2) 0.032 (0.8) 1.50 (38.1)
(N)AS-2B
0.303 (7.7) 0.025 (0.64) 1.50 (38.1)
0.115
0.256(6.5) 0.540(13.7)(2.9) 0.219 (5.6) 0.663 (16.6) 0.032 (0.8) 1.30 (33.0)
(N)AS-2C
0.489(11.0)(6.3) 0.157 (4.0) 0.594 (15.1) 0.032 (0.8) 1.30 (33.0)
0.600 (15.2) 0.032 (0.8) 1.50 (38.1)
0.250
0.480(12.2)
D
(N)AS-3
0.687(17.5)(5.6) 0.282 (7.2) 0.812 (20.6) 0.040 (1.0) 1.50 (38.1)
1.30 (33.0)
0.663 (16.6) 0.032 (0.8)
0.219
0.540(13.7)
(N)AS-5
0.875(22.2)(4.0) 0.344 (8.8) 0.980 (24.9) 0.040 (1.0) 1.50 (38.1)
0.594 (15.1) 0.032 (0.8) 1.30 (33.0)
0.157
0.489(11.0)
(N)AS-7
0.812 (20.6) 0.040 (1.0) 1.50 (38.1)
0.282
0.687(17.5)1.250(31.8)(7.2) 0.344 (8.8) 1.375 (35.0) 0.040 (1.0) 1.50 (38.1)
(N)AS-10
0.980 (24.9) 0.040 (1.0) 1.50 (38.1)
0.344
0.875(22.2)1.812(46.0)(8.8) 0.385 (9.8) 1.937 (49.2) 0.040 (1.0) 1.50 (38.1)
1.250(31.8)
1.812(46.0)
0.344 (8.8) 1.375 (35.0)
0.385 (9.8) 1.937 (49.2)
0.040 (1.0)
0.040 (1.0)
1.50 (38.1)
1.50 (38.1)
D
E
E
A
A
B
C
B
C
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
General Note
General Note
Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
©
Welwyn Components reserves the right to make changes in product specification
or liability.
TT Electronics reserves the right to make changes in product specification without notice
without notice or liability.
Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 · of going to print.
All information is subject to Welwyn’s own data ·and is considered accurate at time Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
Issue D · 03.06
06.20
A subsidiary of
TT electronics plc
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
© TT Electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670
Issue D · 03.06
A subsidiary of
TT electronics plc
www.ttelectronics.com/resistors
9
91
Semi-Precision Non-Inductive
Power Wirewound Resistors
Semi-Precision Power
Power
Wirewound Resistor
Wirewound Resistor
AS Series
AS Series
Performance Data
Power Derating
Power Derating
200
200
175
175
150
150
125
125
NAS-2B
AS-2B
100
100
75
75
0
25
0
25
NAS-1/4, 1/2, 1, 1C
AS-1/4, 1/2, 1, 1C
NAS-3, 2
AS-3, 2
NAS-2C
AS-2C
NAS-5, 10
AS-5, 10
Semi-Precision
NAS Series
Welwyn Components
Welwyn Components
Temperature Rise @ 25°C
Temperature Rise @ 25°C
275
275
250
250
200
200
150
150
100
100
50
50
25
25
0
0
NAS-7, 10
AS-7, 10
NAS-3, 5
AS-3, AS-5
NAS-2C
AS-2C
NAS-1,2
AS-1,2
NAS-2B
AS-2B
NAS-1C
AS-1C
NAS-1/2
AS-1/2
NAS-1/4
AS-1/4
Percent of 125C Power Rating
Percent of 125C Power Rating
NAS-7
AS-7
Hot
Hot Spot Temperature (C)
Spot Temperature (C)
75
75
125
175
125
175
Ambient Temperature (C)
Ambient Temperature (C)
225
225
275
275
40
80
120
40
Percent of 25C Power Rating
80
120
Percent of 25C Power Rating
160
160
200
200
Temperature Rise @ 125°C
Temperature Rise @ 125°C
275
275
250
250
NAS-7, 10
AS-7, 10
NAS-3, 5
AS-3, AS-5
NAS-2C
AS-2C
NAS-1,2
AS-1,2
NAS-2B
AS-2B
NAS-1C
AS-1C
NAS-1/2
AS-1/2
Selected Pulse-Handling Capability @ 125°C
Selected Pulse-Handling Capability @ 125°C
14
14
12
12
10
10
Hot
Hot Spot Temperature (
°C)
°C)
Spot Temperature (
NAS-2
AS-2
Energy (watts-second)
Energy (watts-second)
NAS-3
AS-3
200
200
8
8
6
6
4
4
2
2
NAS-1/2
AS-1/2
NAS-1/4
AS-1/4
0.2
0.2
NAS-1
AS-1
NAS-2B
AS-2B
NAS-2C
AS-2C
NAS-1/4
AS-1/4
150
150
125
125
0
0
40
80
120
160
40
Percent of
80
120
Rating
160
125
°C
Power
Percent of 125
°C
Power Rating
200
200
0
0.1
0
0.1
0.5
1
2
0.5
Resistance (ohms)
2
1
Resistance (ohms)
5
5
10
10
Environmental Testing at 25°C
Environmental Testing
Environmental Testing at 25°C
Test Condition
Test
Life 1000
Load
Condition
hours
Load Life 1000 hours
Moisture Resistance
Moisture Resistance
Temperature Cycle
Temperature Cycle
Short Time Overload
Short Time Overload
Low Temperature Operation
Low Temperature Operation
Solder Heat
Solder
Shock
Heat
Shock
Vibration
Vibration
Max
∆R
Max
∆R
1.0%
1.0%
1.0%
1.0%
0.5%
0.5%
0.5%
0.5%
0.5%
0.5%
0.25%
0.25%
0.5%
0.5%
0.5%
0.5%
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
06.20
Semi-Precision Non-Inductive
Power Wirewound Resistors
NAS Series
Ordering Procedure
Ordering Procedure
This product has two valid part numbers:
European (Welwyn) Part Number: NAS3-2K7FI
(NAS3, 2.7 kilohms ±1%, Pb-free)
N
A
S
1
1
Type
NAS1/4, NAS1/2
NAS1, NAS1C
NAS2, NAS2B
NAS2C, NAS3
NAS5, NAS7, NAS10
2
Value
3
-
2
K
2
3
Tolerance
7
F
3
I
4
4
Termination & Packing
1
I = Pb-free, Standard pack (73mm tape & reel)
Tape & reel pack quantities
NAS-1/4 to NAS-7
1000/reel
NAS-10
500/reel
E24 = 3/4 D = ±0.5%
F = ±1%
characters
R = ohms
H = ±3%
K = kilohms J = ±5%
Note 1: For alternative packing options, use USA part number format.
USA (IRC) Part Number: NAS32701FLF
(NAS3, 2.7 kilohms ±1 Pb-free)
%,
N
A
S
1
1
Type
NAS1/4, NAS1/2
NAS1, NAS1C
NAS2, NAS2B
NAS2C, NAS3
NAS5, NAS7, NAS10
2
Value
3 digits +
multiplier
R = ohms for
values <100
ohms
3
2
7
2
0
1
F
3
3
Tolerance
D = ±0.5%
F = ±1%
H = ±3%
J = ±5%
L
4
4
Termination
F
5
5
Packing
1
Omit for SnPb
Omit for standard (73mm) tape & reel
LF = Pb-free BLK
All sizes
Bulk
NAS-1/4,
Non-standard (63.5mm)
TAF
NAS-1C
tape & reel
NAS-1,
Non-standard (52.4mm)
TAE
NAS-1C
tape & reel
Non-standard (63.5mm)
TBD
NAS-2
tape & reel
NAS-2,
Non-standard (52.4mm)
TBC
NAS-2B
tape & reel
Tape & reel pack quantities
NAS-1/4 to NAS-7
1000/reel
NAS-10
500/reel
Note 1: For full details see PS002 - Packing Specification Axial Resistors (IRC Origin):
Note 1: For full details see PS002 - Packing Specification Axial Resistors (IRC Origin):
https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Resistors/ApplicationNotes/PS002-Packing-of-Axial-Resistors-IRC-Origin.pdf
h½ps://www.½electronics.com/TTElectronics/media/ProductFiles/Resistors/Applica½onNotes/PS002 -Packing-of-Axial-Resistors-IRC-Origin.pdf
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
06.20
