Vitreous Enamelled
Vitreous Enamelled
Wirewound Resistors
Wirewound Resistors
Welwyn Components
W20 Series
W20 Series
CECC approved
CECC approved
Suitable for harsh environments
Suitable for harsh environments
Impervious lead free vitreous enamel coating
Impervious lead free vitreous enamel coating
Overload characteristics ideal for protection circuits
Overload characteristics ideal
High stability and reliability
for protection circuits
High power dissipation for size
High stability and reliability
·
·
·
·
·
·
High power dissipation for size
Electrical Data
Commercial
Power rating at 25°C
Resistance range at 1% tolerance
2% tolerance
5% tolerance
TCR (-55° to 200°C)
watts
ohms
ohms
ohms
pp/°C
BS CECC 40-201-002 Requirements
Power rating at 25°C
Power rating at 70°C
Resistance range at 1% tolerance
2% tolerance
5% tolerance
TCR (-55° to 200°C)
Style
watts
watts
ohms
ohms
ohms
ppm/°C
W21
3.0
1R to 10K
0R5 to 10K
0R1 to 10K
W215
W22
W23
W24
5.0
7.0
10.5
14.0
1R to 15K
1R to 22K
1R to 60K 1R to 100K
0R5 to 15K 0R5 to 22K 1R to 60K 1R to 100K
0R1 to 15K 0R1 to 22K 0R15 to 60K 0R2 to 100K
Typically: <+-75
Maximum: +-200
JB
HB
KB
LB
MB
2.9
5.0
7.0
10.5
14.0
2.5
4.3
6.0
9.0
12.0
1R to 10K
1R to 15K
1R to 20K
1R to 56K 1R to 100K
0R5 to 10K 0R5 to 15K 0R5 to 20K 1R to 56K 1R to 100K
0R1 to 10K 0R1 to 15K 0R1 to 20K 0R15 to 56K 0R2 to 100K
≥5 ohms < 10 ohms: ±400
≥10 ohms: ±200
This table indicates the CECC specification requirements, and these are met or exceeded by the corresponding W20 series products
Applicable to commercial and approved ranges
Limiting element voltage
Standard values
Thermal impedance
Ambient temperature range
volts
100
°C/watt
°C
88
160
200
500
E24 preferred. Other values to special order
58
44
29
-55 to 200
750
22
Physical Data
Dimensions
Type
W21
W215
W22
W23
W24
(mm) and Weight (g)
L max
D max
12.7
5.6
22.0
7.0
22.0
8.0
38.0
8.0
53.5
8.0
400
W215
°C
W21
W24
W22
300
Temperature Rise
W23
d nom
0.8
0.8
0.8
0.8
0.8
Wt.nom
1
2
2
3.5
5
d
D
L
f
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
200
Material
Strength
Solderability
Length
100
0
f min
22.75
23.1
23.1
-
0
5
10
15
20
Dissipation – Watts
Copper clad steel wire, nickel plated and solder-coated.
The terminations meet the requirements of IEC 68.2.21.
The terminations meet the requirements of IEC 115-1,– Clause 4.17.3.2.
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.
General Note
General Note
Welwyn Components reserves to right to make changes in product specification without notice or
TT electronics reserves the right themake changes in product specification without notice or liability. liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
A subsidiary of
TT electronics plc
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
© TT electronics plc822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670
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