Aluminium Housed

Wirewound Resistors

WH Series

conductivity to heatsink

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

107

WH5

WH10

WH25

WH50

Notes

Power rating at 25°C

watts

10

15

25

50*

Mounted on standard heatsink

Resistance range

ohms

0R01 to 10K

0R01 to 20K

0R01 to 44K

0R015 to 120K

TCR (-55° to 200°C)

ppm/°C

<10

Ω : ±75

≥ to <100 : ±50

≥100Ω : ±25

Resistance tolerance

%

1, 2, 5, 10

Low value limits

ohms

1 at 1%

0.5 at 2%

0.05 at 5%

0.01 at 10%

WH50 0.015 at 10%

Approved CECC 40203 - 006

AA

BA

CA

DA

Power rating at 25°C

watts

10

15

25

40

Mounted on standard heatsink

Resistance range

ohms

0.05 to 3.4k

0.05 to 15k

0.05 to 33k

0.05 to 82k

TCR (-55° to 200°C)

ppm/°C

≥5Ω≤ 10Ω ± 100

>10

Ω ±50

Resistance tolerance

%

1, 2, 5

Low value limits

ohms

1 at 1%

0.5 at 2%

0.05 at 5%

WH50 0.015 at 10%

Limiting element voltage

volts

150

250

500

1250

Standard values

E24 preferred range

Other values to special order

Thermal impedance

°C/watt

16.0

10.0

6.0

3.5

Mounted on standard heatsink

Ambient temperature range

°C

-55 to 200

*For load at maximum rating mount on heatsink 30.5 cm x 30.5 cm x 1.5 mm

Electrical Data

Issue D · 03.06

A subsidiary of

TT electronics plc

Welwyn Components

Construction

Cap and lead assemblies are fitted to a high purity ceramic

substrate. The resistive element is wound onto the substrate

and welded to the caps. The wound rod is then moulded and

fitted into an aluminium housing to give optimum stability

and reliability.

Terminations

Material

Solder dipped, copper clad steel wire.

Strength

The terminations meet the requirements of

IEC 68.2.21

Solderability

The terminations meet the requirements of

IEC 115-1, Clause 4.17.3.2

Marking

The resistors are legend marked with type reference,

resistance value and tolerance which will withstand all

accepted industrial cleaning fluids. Values are marked in

accordance with IEC 62.