Electrical Data
Commercial
W21
W215
W22
W23
W24
Power rating at 25°C
watts
3.0
5.0
7.0
10.0
14.0
Resistance range at
1% tolerance
ohms
1 to 10k
1 to 15k
1 to 22k
1 to 60k
1 to 100k
2% tolerance
ohms
0.5 to 10k
0.5 to 15k
0.5 to 22k
1 to 60k
1 to 100k
5% tolerance
ohms
0.1 to 10k
0.1 to 15k
0.1 to 22k
0.15 to 60k
0.2 to 100k
TCR (-55° to 200°C)
pp/°C
Typically: <+75
Maximum: +200
Approved BS CECC 40-201-002
Style
JB
HB
KB
LB
MB
Power rating at 25°C
watts
2.9
5.0
7.0
10.0
14.0
Power rating at 70°C
watts
2.5
4.3
6.0
9.0
12.0
Resistance range at
1% tolerance
ohms
1 to 10k
1 to 15k
1 to 20k
1 to 56k
1 to 100k
2% tolerance
ohms
0.5 to 10k
0.5 to 15k
0.5 to 20k
1 to 56k
1 to 100k
5% tolerance
ohms
0.1 to 10k
0.1 to 15k
0.1 to 20k
0.15 to 56k
0.2 to 100k
TCR (-55° to 200°C)
ppm/°C
≥5 ohms < 10 ohms: ±400
≥10 ohms: ±200
Applicable to commercial and approved ranges
Limiting element voltage
volts
100
160
200
500
750
Standard values
E24 preferred. Other values to special order
Thermal impedance
°C/watt
88
58
44
29
22
Ambient temperature range
°C
-55 to 200
Physical Data
Dimensions (mm) & weight (g)
Type
L max
D max
f min
d nom
Wt.nom
W21
12.7
5.6
22.75
0.8
1
W215
22.0
7.0
23.1
0.8
2
W22
22.0
8.0
23.1
0.8
2
W23
38.0
8.0
-
0.8
3.5
W24
53.5
8.0
-
0.8
5
CONSTRUCTION
A high purity ceramic substrate is assembled with interference fit end caps to which
are welded the termination wires. The resistive element is wound on the substrate
and welded to the caps; the vitreous enamel protective coating is then applied.
TERMINATIONS
Material
Copper clad steel wire, nickel plated and solder-coated.
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.
Length
W23’s and W24’s are not supplied on tape.
Minimum lead length is 30 mm.
MARKING
The resistors are legend marked with type reference, resistance value and tolerance.
Values are marked in accordance with IEC 62.
SOLVENT RESISTANCE
The body protection and marking are resistant to all normal industrial cleaning
solvents suitable for printed circuits.
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, England Tel: 01670 822181 Fax: 01670 829465 Web: http://www.Welwyn-TT.co.uk
Issue A 07/99
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.
Vitreous Enamelled
Wirewound Resistors
W20 SERIES
● All welded construction
● High purity ceramic substrate
● Impervious lead free vitreous enamel coating
● High power dissipation for size
● High stability and reliability
● Suitable for harsh environments
● Overload characteristics ideal
for protection circuits
L
D
f
d dia
0
5
10
15
20
W21
W215
W22
W23
W24
400
300
200
100
0
Dissipation – Watts
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