WSM1

WSM2

WSM3

Power rating at 70°C

watts

1

2

3

Resistance range

ohms

0R01 to 1K

0R01 to 2K

0R01 to 3K

Limiting element voltage

volts

100

TCR

ppm/°C

< 1

Ω : 100

< 1

Ω : 100

≤.03 Ω 700 ≤0.1 Ω : 200

≥ 1 Ω : 20

≥ 1 Ω : 20

≤10R 100 >10R 20

Resistance tolerance

%

*1, 2, 5, 10

Standard values

E24 preferred

Ambient temperature range

°C

-55 to 155

Moulded Surface Mount

Wirewound Resistors

WSM Series

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.

Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com

Electrical Data

Issue C · 04.03

A subsidiary of

TT electronics plc

Welwyn Components

45

Dimensions (mm)

Type

L max

I Nom

W Max

w Max

H Max

WSM1

7.9

2.54

7

4.2

3.94

WSM2

12

3.1

10.5

6.6

5.5

WSM3

18

3.1

16

7

6.5

Type

A

B

C

D

WSM1

2.9

2.6

2.8

8.1

WSM2

3.4

4.0

6

14

WSM3

3.4

4.5

11

20

Physical Data

Recommended Pad Sizes

L

W

w

I

H

B

C

D

A

Marking

WSM resistors are legend marked with type value and

tolerance.

WSM1 Resistors are marked with value and tolerance.

Solvent Resistance

The body protection and marking are resistant to all normal

industrial cleaning solvents suitable for printed circuits.

Construction

A high purity ceramic substrate is assembled with interference

fit end caps to which are welded the terminations. The

resistive element is wound on the substrate and welded to

the caps. The unit is then moulded.

Flammability

The resistor coating is a flame retardant epoxy to UL 94.

*Note 5% or 10% preferred below 0.1 ohms

WSM_C.qxd

29/4/03

10:38 am

Page 1