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

Issue G · 03.06

Welwyn Components

Marking

WA83Z and WA84Z resistors R10 and above are marked with

four colour bands in conformance with IEC62. Values

below R10 are marked with three bands (two digits and

tolerance); there is no multiplier band. WA85Z resistors are

legendmarked “WA85” plus resistance value and tolerance in

conformance with IEC62.

Solvent Resistance

The body protection and marking are resistant to all normal

industrial cleaning solvents suitable for printed circuits.

Flammability

The resistor coating will not burn under any condition of

applied temperature or component overload.

WA80Z Thermal Performance

0

20

40

60

80

100

120

140

160

180

200

220

240

260

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Power (W)

WA83Z Hot Spot

WA83Z Joint

WA84Z Hot Spot

WA84Z Joint

WA85Z Hot Spot

WA85Z Joint

Graph 1

Performance Data

Temperature Rise

Maximum

Typical

Load at rated power: 1000hrs @ 25 or 70°C

∆R%

5 +0.001

Ω

3

Dry heat: 1000hrs @ 200°C

∆R%

5 +0.001

Ω

3

Short term overload

∆R%

5 +0.001

Ω

1

Derating from rated power @ 25°C

Zero at 155˚C

Climatic

∆R%

5 +0.001

Ω

2

Climatic category

55/200/56

TRC & Vibration

∆R%

5 +0.001

Ω

1

Robustness & solder heat

∆R%

5 +0.001

Ω

1

Long term damp heat

∆R%

5 +0.001

Ω

1

Temperature rise

See Graph 1

Pulse handling

See Graph 2

Cement Coated Surface

Mount Wirewound Resistors

WA80Z Series