Semi-Precision Power
Wirewound Resistor
AS Series
Welwyn Components
•
0.25 to 10 watts
•
Tolerance down to ±0.5%
•
0.1 ohm to 175K ohms
•
Resistance wire TCR ±20 ppm/°C
Electrical Data
Type
AS-
1
/
4
AS-
1
/
2
AS-1
AS-1C
AS-2
AS-2B
AS-2C
AS-3
AS-5
AS-7
AS-10
RW68V/
RW78U
RW74U/
RW67U
7
10
9
14
0.1
0.1
90K
175K
1.0
3.0
45K
50K
1-90K
1-175K
0.1-90K
0.1-175K
RW-69V/
RW79U
3
2
3
5
4
3
5
7
0.1
0.1
0.1
0.1
24K
18K
30K
60K
0.5
0.2
0.5
0.8
12K
7.5K
15K
30K
1-24K
1-18K
1-30K
1-60K
0.1-24K
0.1-18K
0.1-30K
0.1-60K
RW70U
Equivalent
MIL-R-26
Style
RW81
Power Rating
(watts)
125°C
25°C
0.5
0.5
1
1
2
1
1
2
2
3
Commercial Range
(ohms)
Min.
Max.
0.1
0.1
0.1
.05
0.1
1.0K
6.0K
7.5K
2K
20K
Non-Inductive Range
(ohms)
Min.
Max.
*
*
0.1
*
0.5
*
*
3.8K
*
10K
Available Resistance
(ohms)
0.5%, 1%
3%, 5%
1-1K
1-6K
1-7.5K
1-2K
1-20K
0.1-1K
0.1-6K
0.1-7.5K
.05-2K
0.1-20K
Inductance of AS-1/2 is less than 1µH at 1MHz.
To order non-inductive types, add the prefix ‘N’. Example: NAS-1, NAS-2C, etc.
* Typical inductance of AS-1C <5ohms is <1µH.
Lower values available upon request.
Physical Data
Dimensions (mm)
Type
AS-
1
/
4
AS-
1
/
2
AS-1
AS-1C
AS-2
AS-2B
AS-2C
AS-3
AS-5
AS-7
AS-10
A ±0.81
6.4
7.9
9.3
6.5
12.2
13.7
11.0
17.5
22.2
31.8
46.0
B (max)
2.4
2.4
3.2
2.9
6.3
5.6
4.0
7.2
8.8
8.8
9.8
C (max)
7.9
9.5
10.9
7.7
15.2
16.6
15.1
20.6
24.9
35.0
49.2
0.5
0.64
0.8
0.8
0.8
1.0
1.0
1.0
1.0
D (Lead Diameter)
0.5
0.5
0.64
0.8
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.
1.50 min.
(38.1)
D
A
B
C
* 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
Issue D · 03.06
© 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
Semi-Precision Power
Wirewound Resistor
AS Series
Power Derating
200
AS-1/4, 1/2, 1, 1C
Percent of 125C Power Rating
175
Hot Spot Temperature (C)
AS-3, 2
150
AS-2C
AS-5, 10
125
AS-2B
100
AS-7
75
0
25
200
AS-2A, 2C
150
AS-1/2
100
AS-1/4
50
25
75
125
175
225
275
0
40
80
120
160
200
Welwyn Components
Temperature Rise @ 25°C
275
250
AS-7, 10
AS-2A, 2C
AS-3, AS-5
AS-2B
Ambient Temperature (C)
Percent of 25C Power Rating
Temperature Rise @ 125°C
275
AS-7, 10
250
Hot Spot Temperature (°C)
AS-2
AS-2A, 2C
AS-1/2
200
AS-1/4
Selected Pulse-Handling Capability @ 125°C
14
AS-2A
12
Energy (watts-second)
AS-2
AS-3
AS-3, AS-5
AS-2B
10
8
AS-2B
6
AS-2C
4
AS-1
2
0
0.1
150
125
0
AS-1/2
AS-1/4
0.2
0.5
1
2
Resistance (ohms)
5
10
40
80
120
160
200
Percent of 125°C Power Rating
Environmental Testing at 25°C
Test Condition
Load Life 1000 hours
Moisture Resistance
Temperature Cycle
Short Time Overload
Low Temperature Operation
Solder Heat
Shock
Vibration
Max
∆R
1.0%
1.0%
0.5%
0.5%
0.5%
0.25%
0.5%
0.5%
Packaging
Parts are supplied taped and reeled.
Standard quantity per reel.
Standard Quantities Per Package
AS
1
/
4
,
1
/
2
, 1C
AS 1, 2, 2B, 2C
AS 3
AS 5, 7, 10
2,000
1,000
1,000
500
© 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
Semi-Precision Power
Wirewound Resistor
AS Series
Welwyn Components
Ordering Procedure
Specify type reference, value and tolerance as shown in this example of AS1/4 1K0 5%:
Type
Resistance value
(IEC62 code)
Tolerance
(IEC62 code)
F
G
J
1%
2%
5%
AS1/4
1K0
J
© 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
Power technology
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