Semi-Precision Power
Wirewound Resistor
(N)AS Series
0.25to10was
Tolerance down to ±0.5%
0.1ohmto150Kohms
ResistancewireTCR±20ppm/°C
Noninducve(NAS)opon
Pb-freeoponisRoHScompliant
Semi-Precision Power
Wirewound Resistor
AS Series
•0.25 to 10 watts
•Tolerance down to ±0.5%
•0.1 ohm to 175K ohms
•Resistance wire TCR ±20 ppm/°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.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
91
Issue D · 03.06
A subsidiary of
TT electronics plc
Welwyn Components
Dimensions Inches (mm)
Type
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
Physical Data
AE
D
C
B
Electrical Data
Equivalent Power Rating AS Standard Range
MIL-R-26 (watts) (ohms)
Type Style 125°C 25°C Min. Max. Min. Max.
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
RW81
RW70U
RW79U
RW74U
RW78U
0.25
0.5
1
1
2
3
2
3
5
7
10
A ±0.032 (0.81)
0.250(6.4)
0.312(7.9)
0.367(9.3)
0.256(6.5)
0.480(12.2)
0.540(13.7)
0.489(11.0)
0.687(17.5)
0.875(22.2)
1.250(31.8)
1.812(46.0)
B (max)
0.094 (2.4)
0.094 (2.4)
0.125 (3.2)
0.115 (2.9)
0.250 (6.3)
0.219 (5.6)
0.157 (4.0)
0.282 (7.2)
0.344 (8.8)
0.344 (8.8)
0.385 (9.8)
C (max)
0.312 (7.9)
0.375 (9.5)
0.429 (10.9)
0.303 (7.7)
0.600 (15.2)
0.663 (16.6)
0.594 (15.1)
0.812 (20.6)
0.980 (24.9)
1.375 (35.0)
1.937 (49.2)
D (nom)
0.020 (0.5)
0.020 (0.5)
0.020 (0.5)
0.025 (0.64)
0.032 (0.8)
0.032 (0.8)
0.032 (0.8)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
E (min)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.30 (33.0)
1.30 (33.0)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
0R2
0R24
0R1
R05
0R1
0R1
0R1
0R1
0R1
0R1
0R1
1
1
2
2
3
4
3
5
7
9
14
4K0
6K0
7K5
2K0
20K
33K
18K
30K
60K
90K
150K
1R0
1R0
0R1
10R
0R5
0R5
0R2
0R5
0R8
1R0
0R3
500R
3K0
3K8
1K0
10K
12K
7K5
15K
30K
45K
51K
3, 5 0.5, 1, 3, 5
Available Tolerance (%)
<1R0 ≥1R0
NAS Non-inductive
Range (ohms)
Semi-Precision Power
Wirewound Resistor
AS Series
•0.25 to 10 watts
•Tolerance down to ±0.5%
•0.1 ohm to 175K ohms
•Resistance wire TCR ±20 ppm/°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.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
91
Issue D · 03.06
A subsidiary of
TT electronics plc
Welwyn Components
Dimensions Inches (mm)
Type
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
Physical Data
AE
D
C
B
Electrical Data
Equivalent Power Rating AS Standard Range
MIL-R-26 (watts) (ohms)
Type Style 125°C 25°C Min. Max. Min. Max.
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
RW81
RW70U
RW79U
RW74U
RW78U
0.25
0.5
1
1
2
3
2
3
5
7
10
A ±0.032 (0.81)
0.250(6.4)
0.312(7.9)
0.367(9.3)
0.256(6.5)
0.480(12.2)
0.540(13.7)
0.489(11.0)
0.687(17.5)
0.875(22.2)
1.250(31.8)
1.812(46.0)
B (max)
0.094 (2.4)
0.094 (2.4)
0.125 (3.2)
0.115 (2.9)
0.250 (6.3)
0.219 (5.6)
0.157 (4.0)
0.282 (7.2)
0.344 (8.8)
0.344 (8.8)
0.385 (9.8)
C (max)
0.312 (7.9)
0.375 (9.5)
0.429 (10.9)
0.303 (7.7)
0.600 (15.2)
0.663 (16.6)
0.594 (15.1)
0.812 (20.6)
0.980 (24.9)
1.375 (35.0)
1.937 (49.2)
D (nom)
0.020 (0.5)
0.020 (0.5)
0.020 (0.5)
0.025 (0.64)
0.032 (0.8)
0.032 (0.8)
0.032 (0.8)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
E (min)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.30 (33.0)
1.30 (33.0)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
0R2
0R24
0R1
R05
0R1
0R1
0R1
0R1
0R1
0R1
0R1
1
1
2
2
3
4
3
5
7
9
14
4K0
6K0
7K5
2K0
20K
33K
18K
30K
60K
90K
150K
1R0
1R0
0R1
10R
0R5
0R5
0R2
0R5
0R8
1R0
0R3
500R
3K0
3K8
1K0
10K
12K
7K5
15K
30K
45K
51K
3, 5 0.5, 1, 3, 5
Available Tolerance (%)
<1R0 ≥1R0
NAS Non-inductive
Range (ohms)
Semi-Precision Power
Wirewound Resistor
AS Series
•0.25 to 10 watts
•Tolerance down to ±0.5%
•0.1 ohm to 175K ohms
•Resistance wire TCR ±20 ppm/°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.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
91
Issue D · 03.06
A subsidiary of
TT electronics plc
Welwyn Components
Dimensions Inches (mm)
Type
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
Physical Data
AE
D
C
B
Electrical Data
Equivalent Power Rating AS Standard Range
MIL-R-26 (watts) (ohms)
Type Style 125°C 25°C Min. Max. Min. Max.
(N)AS-1/4
(N)AS-1/2
(N)AS-1
(N)AS-1C
(N)AS-2
(N)AS-2B
(N)AS-2C
(N)AS-3
(N)AS-5
(N)AS-7
(N)AS-10
RW81
RW70U
RW79U
RW74U
RW78U
0.25
0.5
1
1
2
3
2
3
5
7
10
A ±0.032 (0.81)
0.250(6.4)
0.312(7.9)
0.367(9.3)
0.256(6.5)
0.480(12.2)
0.540(13.7)
0.489(11.0)
0.687(17.5)
0.875(22.2)
1.250(31.8)
1.812(46.0)
B (max)
0.094 (2.4)
0.094 (2.4)
0.125 (3.2)
0.115 (2.9)
0.250 (6.3)
0.219 (5.6)
0.157 (4.0)
0.282 (7.2)
0.344 (8.8)
0.344 (8.8)
0.385 (9.8)
C (max)
0.312 (7.9)
0.375 (9.5)
0.429 (10.9)
0.303 (7.7)
0.600 (15.2)
0.663 (16.6)
0.594 (15.1)
0.812 (20.6)
0.980 (24.9)
1.375 (35.0)
1.937 (49.2)
D (nom)
0.020 (0.5)
0.020 (0.5)
0.020 (0.5)
0.025 (0.64)
0.032 (0.8)
0.032 (0.8)
0.032 (0.8)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
0.040 (1.0)
E (min)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.30 (33.0)
1.30 (33.0)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
1.50 (38.1)
0R2
0R24
0R1
R05
0R1
0R1
0R1
0R1
0R1
0R1
0R1
1
1
2
2
3
4
3
5
7
9
14
4K0
6K0
7K5
2K0
20K
33K
18K
30K
60K
90K
150K
1R0
1R0
0R1
10R
0R5
0R5
0R2
0R5
0R8
1R0
0R3
500R
3K0
3K8
1K0
10K
12K
7K5
15K
30K
45K
51K
3, 5 0.5, 1, 3, 5
Available Tolerance (%)
<1R0 ≥1R0
NAS Non-inductive
Range (ohms)
Resistors
BI Technologies IRC Welwyn
05.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
AllPb-freepartscomplywithEUDirecve2011/65/EUamendedby(EU)2015/863(RoHS3)AllPb-freepartscomplywithEUDirecve2011/65/EUamendedby(EU)2015/863(RoHS3)
Standard winding (AS...) OBSOLETE
(N)AS Series
Semi-Precision Power
Wirewound Resistor
AS Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
92
Issue D · 03.06
Welwyn Components
Power Derating Temperature Rise @ 25°C
Selected Pulse-Handling Capability @ 125°CTemperature Rise @ 125°C
200
175
150
125
100
75
0
Percent of 125C Power Rating
Ambient Temperature (C)
AS-1/4, 1/2, 1, 1C
AS-3, 2
AS-2C
AS-5, 10
AS-2B
AS-7
25 75 125 175 225 275
275
250
200
150
100
50
25
Hot Spot Temperature (C)
Percent of 25C Power Rating
AS-1/4
AS-7, 10
AS-1/2
AS-2C
AS-3, AS-5
AS-2B AS-1C
0 40 80 120 160 200
AS-1,2
275
250
200
150
125
Hot Spot Temperature ( °C)
Percent of 125 °C Power Rating
AS-1,2
AS-7, 10
AS-1/2
AS-1/4
AS-2C
AS-3, AS-5 AS-2B AS-1C
0 40 80 120 160 200
14
12
10
8
6
4
2
0
Energy (watts-second)
Resistance (ohms)
AS-3
AS-2B
AS-2
AS-2C
AS-1
AS-1/2
AS-1/4
0.1 0.2 0.5 1 2 5 10
Test Condition Max ∆R
Load Life 1000 hours 1.0%
Moisture Resistance 1.0%
Temperature Cycle 0.5%
Short Time Overload 0.5%
Low Temperature Operation 0.5%
Solder Heat 0.25%
Shock 0.5%
Vibration 0.5%
Environmental Testing at 25°C
Semi-Precision Power
Wirewound Resistor
AS Series
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
92
Issue D · 03.06
Welwyn Components
Power Derating Temperature Rise @ 25°C
Selected Pulse-Handling Capability @ 125°CTemperature Rise @ 125°C
200
175
150
125
100
75
0
Percent of 125C Power Rating
Ambient Temperature (C)
AS-1/4, 1/2, 1, 1C
AS-3, 2
AS-2C
AS-5, 10
AS-2B
AS-7
25 75 125 175 225 275
275
250
200
150
100
50
25
Hot Spot Temperature (C)
Percent of 25C Power Rating
AS-1/4
AS-7, 10
AS-1/2
AS-2C
AS-3, AS-5
AS-2B AS-1C
0 40 80 120 160 200
AS-1,2
275
250
200
150
125
Hot Spot Temperature ( °C)
Percent of 125 °C Power Rating
AS-1,2
AS-7, 10
AS-1/2
AS-1/4
AS-2C
AS-3, AS-5 AS-2B AS-1C
0 40 80 120 160 200
14
12
10
8
6
4
2
0
Energy (watts-second)
Resistance (ohms)
AS-3
AS-2B
AS-2
AS-2C
AS-1
AS-1/2
AS-1/4
0.1 0.2 0.5 1 2 5 10
Test Condition Max ∆R
Load Life 1000 hours 1.0%
Moisture Resistance 1.0%
Temperature Cycle 0.5%
Short Time Overload 0.5%
Low Temperature Operation 0.5%
Solder Heat 0.25%
Shock 0.5%
Vibration 0.5%
Environmental Testing at 25°C
EnvironmentalTesng
PerformanceData
BI Technologies IRC Welwyn
05.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
Semi-Precision Power Wirewound Resistor
Standard winding (AS...) OBSOLETE
OrderingProcedure
BI Technologies IRC Welwyn
05.20
General Note
TT Electronics reserves the right to make changes in product specication without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
© TT Electronics plc
www.ttelectronics.com/resistors
(N)AS Series
Semi-Precision Power Wirewound Resistor
Ordering Procedure
This product has two valid part numbers:
European (Welwyn) Part Number: AS3-27KFI (AS3, 27 kilohms ±1%, Pb-free)
A
S
3
-
2
7
K
F
I
2
3
4
5
Note 1: For alternative packing options, use USA part number format.
USA (IRC) Part Number: AS32702FLF (AS3, 27 kilohms ±1%, Pb-free)
A
S
3
2
7
0
2
F
L
F
2
3
4
5
6
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
1
2
3
4
5
Winding Type Value Tolerance Termination & Packing1
Omit for
standard
AS1/4, AS1/2
AS1, AS1C
AS2, AS2B
AS2C, AS3
AS5, AS7, AS10
E24 = 3/4
characters
R = ohms
K = kilohms
D = ±0.5%
I = Pb-free, Standard pack (73mm tape & reel)
F = ±1%
Tape & reel pack quantities
N = non-
inductive
H = ±3%
AS-1/4 to AS-7
1000/reel
J = ±5%
AS-10
500/reel
1
2
3
4
5
6
Winding Type Value Tolerance Termination Packing1
Omit for
standard
AS1/4, AS1/2
AS1, AS1C
AS2, AS2B
AS2C, AS3
AS5, AS7, AS10
3 digits +
multiplier
D = ±0.5%
Omit for SnPb
Omit for standard (73mm) tape & reel
F = ±1%
LF = Pb-free
BLK
All sizes
Bulk
N = non-
inductive
R = ohms for
values <100
ohms
H = ±3%
TAF
AS-1/4,
AS-1C
Non-standard (63.5mm)
tape & reel
J = ±5%
TAE
AS-1,
AS-1C
Non-standard (52.4mm)
tape & reel
TBD
AS-2
Non-standard (63.5mm)
tape & reel
TBC
AS-2,
AS-2B
Non-standard (52.4mm)
tape & reel
Tape & reel pack quantities
AS-1/4 to AS-7
1000/reel
AS-10
500/reel
Standard winding (AS...) OBSOLETE