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 (mm)
Type A ±0.81 B (max) C (max) D (Lead Diameter)
AS-1/46.4 2.4 7.9 0.5
AS-1/27.9 2.4 9.5 0.5
AS-1 9.3 3.2 10.9 0.5 0.64
AS-1C 6.5 2.9 7.7 0.64 0.8
AS-2 12.2 6.3 15.2 0.8
AS-2B 13.7 5.6 16.6 0.8
AS-2C 11.0 4.0 15.1 0.8
AS-3 17.5 7.2 20.6 1.0
AS-5 22.2 8.8 24.9 1.0
AS-7 31.8 8.8 35.0 1.0
AS-10 46.0 9.8 49.2 1.0
* Leads are solder plated. AS-1C leads are copper. All others are 40% conductivity copper sheathed steel.
Electrical Data
Equivalent Power Rating Commercial Range Non-Inductive Range Available Resistance
MIL-R-26 (watts) (ohms) (ohms) (ohms)
Type Style 125°C 25°C Min. Max. Min. Max. 0.5%, 1% 3%, 5%
AS-1/4RW81 0.5 1 0.1 1.0K * * 1-1K 0.1-1K
AS-1/20.5 1 0.1 6.0K * * 1-6K 0.1-6K
AS-1 RW70U 1 2 0.1 7.5K 0.1 3.8K 1-7.5K 0.1-7.5K
AS-1C 1 2 .05 2K * * 1-2K .05-2K
AS-2 RW-69V/ 2 3 0.1 20K 0.5 10K 1-20K 0.1-20K
RW79U
AS-2B 3 4 0.1 24K 0.5 12K 1-24K 0.1-24K
AS-2C 2 3 0.1 18K 0.2 7.5K 1-18K 0.1-18K
AS-3 3 5 0.1 30K 0.5 15K 1-30K 0.1-30K
AS-5 RW74U/ 5 7 0.1 60K 0.8 30K 1-60K 0.1-60K
RW67U
AS-7 7 9 0.1 90K 1.0 45K 1-90K 0.1-90K
AS-10 RW68V/ 10 14 0.1 175K 3.0 50K 1-175K 0.1-175K
RW78U
Inductance of AS-1/2 is less than 1µH at 1MHz. * Typical inductance of AS-1C <5ohms is <1µH.
To order non-inductive types, add the prefix ‘N’. Example: NAS-1, NAS-2C, etc.
Lower values available upon request.
Physical Data
A
D
C
1.50 min.
(38.1)
B
Please note lead length dimension change on the following
two items only:
AS-2B 33.0mm (min)
AS-2C 33.0mm (min)
Note:
• Coating and marking is resistant to normal freon
degreasing.
Consult factory for special requirements.
• AS marking available in Alpha Numeric or Colourbanding -
identification available.
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-2A, 2C
AS-3, AS-5
AS-2B
0 40 80 120 160 200
AS-2A, 2C
275
250
200
150
125
Hot Spot Temperature (°C)
Percent of 125°C Power Rating
AS-2
AS-7, 10
AS-1/2
AS-1/4
AS-2A, 2C
AS-3, AS-5 AS-2B
0 40 80 120 160 200
14
12
10
8
6
4
2
0
Energy (watts-second)
Resistance (ohms)
AS-2A
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 Issue D · 03.06
Welwyn Components
Ordering Procedure
Example: AS1/4 at 1 kilohm and 5% tolerance on a reel of 2000 pieces -
A S 1 / 4 – 1 K 0 J I
Winding
Standard
N
Non-inductive
Type
Value (use IEC62 code)
Tolerance (use IEC62 code)
D
0.5%
H
3%
F
1%
J
5%
Packing
I
Tape
2000/reel
Standard
1000/reel
500/reel