Aluminium Housed

Wirewound Resistors

The standard aluminium heatsinks are defined in the table below. If smaller heatsinks are used then derating should

be applied as indicated in the graph below.

WH200 and WH300 are supplied with a set of four M6 nuts and washers. The screw terminations can support a

maximum tightening torque of 5Nm.

Packaging

WH5-100 resistors are packed in plastic bags and boxed. WH200 & 300 are individually boxed.

Ordering Procedure

Example: WH25 at 100 ohms with a 5% tolerance:

W H 2 5 – 1 0 0 R J I

Type

Value (use IEC62 code)

Tolerance (use IEC62 code)

F

1%

J

5%

G

2%

K

10%

Packing

I

Bulk

All Sizes

Standard

The following options apply to WH5 – 50 only:

For CECC released product state on order the CECC number and style. Example: WH25-3K3JI CECC40203-006 CA

For SnPb finish instead of Pb-free replace the packing suffix with PB. Example: WH25-3K3JPB

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 test data and is considered accurate at time of print.

©Welwyn Components Limited

Welwyn Electronics Park, Bedlington, Northumberland, NE22 7AA, England. Tel: 01670 822181 Fax: 01670 829465 Web: www.welwyn-tt.com

Type (CECC)

Thickness (mm)

Area (cm²)

WH5 (AA)

1

410

WH10 (BA)

1

410

WH25 (CA)

1

544

WH50 (DA)

1

544

WH50 @ 50W

1.5

930

WH100

3

1000

WH200

3

3800

WH300

3

5800

Reference heatsink dimensions

1

10

100

1000

1

10

100

1000

10000

Heatsink Surface Area (cm

WH10/BA 70°C

WH10/BA 25°C

WH5/AA 70°C

WH5/AA 25°C

WH25/CA 70°C

WH25/CA 25°C

DA 70°C

DA 25°C

WH50 25°C

WH100 70°C

WH100 25°C

WH200 70°C

WH200 25°C

WH300 70°C

WH300 25°C

0

20

40

60

80

1 00

1 20

0

100

200

A m b ie n t T e m p e ra tu r e (° C)

Derating for reduced heatsink dimensions

Derating for ambient temperature