ULW2

ULW3

ULW4

Power rating at 25°C

watts

2

3

4

5 second overload rating at 25ºC

watts

10

15

20

Inrush / surge performance

See Pulse Performance graphs

Resistance range

ohms

22 to 100

10 to 100

10

TCR

ppm/°C

±200

Isolation voltage

volts

250

350

500

Resistance tolerance

%

5

UL recognised standard values

ohms

22, 33, 47, 68, 100

10, 22, 27, 33, 47, 68, 100

10

Thermal impedance

°C/watt

110

82

62

Ambient temperature range

°C

-55 to +155

Welwyn Components

A subsidiary of

TT electronics plc

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

03. 09

UL Recognised

Wirewound Resistors

ULW Series

Physical Data

* UL file number E234469.

Electrical Data

Dimensions (mm) and weight (g)

Type

L Max

D Max

f min

d nom

PCB

mount

centres

Min

bend

radius

Min

bend

radius

ULW2

9.0

3.6

19.8

0.8

12.7

1.2

0.5

ULW3

14.5

5.2

24.6

20.3

1.1

ULW4

13

5.6

22.8

18.9

1.0

Note - no limiting element voltage applies; maximum continuous voltage is

√(P.R)

Construction

A high purity ceramic rod is assembled with interference fit end caps to which are welded the terminations. The surge withstanding resistive element

is wound on the rod and welded to the caps. Flameproof fusible cement coating is applied prior to marking with indelible ink. The components are

then leadformed if required and packed.

Marking

ULW2 & ULW3 resistors are marked with five colour bands. The first four indicate value and tolerance in conformance with IEC62. The fifth yellow

band denotes defined fusibility. ULW4 resistors are legend marked with type, value and tolerance.

d

f

L

D