Semi-Precision Power

Wirewound Resistor Welwyn Components

AS Series
• 0.25 to 10 watts
• Tolerance down to ±0.5%
• 0.1 ohm to 175K ohms
• Resistance wire TCR ±20 ppm/°C

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-1/4 RW81 0.5 1 0.1 1.0K * * 1-1K 0.1-1K
AS-1/2 0.5 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
Dimensions (mm)
Type A ±0.81 B (max) C (max) D (Lead Diameter)
1.50 min. A
AS-1/4 6.4 2.4 7.9 0.5 (38.1)
AS-1/2 7.9 2.4 9.5 0.5 D B

AS-1 9.3 3.2 10.9 0.5 0.64 C

AS-1C 6.5 2.9 7.7 0.64 0.8
Please note lead length dimension change on the following
AS-2 12.2 6.3 15.2 0.8 two items only:
AS-2B 13.7 5.6 16.6 0.8 AS-2B 33.0mm (min)
AS-2C 33.0mm (min)
AS-2C 11.0 4.0 15.1 0.8
Note:
AS-3 17.5 7.2 20.6 1.0 • Coating and marking is resistant to normal freon
degreasing.
AS-5 22.2 8.8 24.9 1.0
Consult factory for special requirements.
AS-7 31.8 8.8 35.0 1.0 • AS marking available in Alpha Numeric or Colourbanding -
identification available.
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.

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. A subsidiary of
TT electronics plc
© 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

91
 Semi-Precision Power
Wirewound Resistor
AS Series Welwyn Components

Power Derating Temperature Rise @ 25°C

200 275
AS-7, 10
AS-1/4, 1/2, 1, 1C 250
AS-2A, 2C
Percent of 125C Power Rating

175 AS-3, AS-5

AS-3, 2

Hot Spot Temperature (C)

200
AS-2B
150 AS-2A, 2C
AS-2C
AS-5, 10 150
125 AS-1/2
AS-2B
100
100
AS-7 AS-1/4

50
75
25
0
25 75 125 175 225 275 0 40 80 120 160 200
Ambient Temperature (C) Percent of 25C Power Rating

Temperature Rise @ 125°C Selected Pulse-Handling Capability @ 125°C

275 14
AS-7, 10 AS-2A
12
250
AS-3, AS-5 AS-2 AS-3
AS-2B
Hot Spot Temperature (°C)

Energy (watts-second)

AS-2 10
AS-2A, 2C
AS-1/2 8
200 AS-2B
6

AS-1/4 AS-2C
4
AS-1
150 2
AS-1/2
AS-1/4
125 0
0 40 80 120 160 200 0.1 0.2 0.5 1 2 5 10
Percent of 125°C Power Rating Resistance (ohms)

Environmental Testing at 25°C

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%

© 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

92
Semi-Precision Power
Wirewound Resistor
AS Series Welwyn Components

Ordering Procedure
Example: AS1/4 at 1 kilohm and 5% tolerance on a reel of 2000 pieces -

AS1/4–1K0JI
Winding
Standard
N Non-inductive

Type

Value (use IEC62 code)

Tolerance (use IEC62 code)

D 0.5% H 3%
F 1% J 5%

Packing
AS¼, ½, 1C 2000/reel
I Tape AS1, 2, 2B, 2C, 3 1000/reel Standard
AS5, 7, 10 500/reel

© 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