Resistors
Vitreous Enamelled
Vitreous Enamelled
Resistors
Wirewound
Wirewound Resistors
W20 Series
Welwyn Components
•
CECC approved
W20 Series
Suitable
•
IECQ-CECC
for harsh environments
approved
Impervious lead free vitreous
•
Suitable for harsh environments
enamel coating
Overload characteristics ideal
•
Impervious lead free vitreous enamel coating
•
•
for protection circuits
Overload characteristics ideal for protection circuits
High stability and reliability
High stability and reliability
High power dissipation for size
size
High power dissipation for
All Pb-free parts comply with EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3)
Electrical Data
Commercial
Power rating at 25° C
Resistance range at 1% tolerance
2% tolerance
5% tolerance
TCR (-55° to 200° C)
BS IECQ-CECC 40-201-002 Requirements
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)
watts
ohms
ohms
ohms
ppm/ ° C
Style
watts
watts
ohms
ohms
ohms
ppm/° C
W21
W22
3.0
70
1R to 10K
1R to 22K
0R5 to 10K
0R5 to 22K
0R1 to 10K
0R1 to 22K
Typically: <+-75
JB
2.9
2.5
1R to 10K
0R5 to 10K
0R1 to 10K
≥5
ohms <
.
W23
W24
10.5
14.0
1R to 60K
1R to 100K
1R to 60K
1R to 100K
0R15 to 60K
0R2 to 100K
Maximum: +-200
LB
MB
10.5
14.0
9.0
12.0
1R to 56K
1R to 100K
1R to 56K
1R to 100K
0R15 to 56K
0R2 to 100K
≥10
ohms: ±200
KB
7.0
6.0
1R to 20K
0R5 to 20K
0R1 to 20K
10 ohms: ±400
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
° C/watt
°C
100
88
200
500
750
E24 preferred. Other values to special order
44
29
22
-55 to 200
Physical Data
Dimensions
Type
W21
W22
W23
W24
400
(mm) and Weight (g)
L max
D max
12.7
5.6
22.0
8.0
38.0
8.0
53.5
8.0
f min
22.75
23.1
-
-
d nom
0.8
0.8
0.8
0.8
Wt.nom
1
2
3.5
5
d
D
L
f
Construction
W21
W23
W22
W24
300
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.
Temperature Rise
°C
Terminations
200
100
Material
Strength
Solderability
Length
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.
0
0
5
10
15
20
Dissipation – Watts
General Note
General Note
The resistors are legend marked with type reference, resistance value and tolerance. Values are
marked in accordance with IEC 62.
Marking
Welwyn Components reserves the right to make changes in product specification
or liability.
TT Electronics reserves the right to make changes in product specification without notice
without notice or 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.
BI Technologies IRC Welwyn
A subsidiary of
TT electronics plc
www.ttelectronics.com/resistors
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
© TT Electronics plc
822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Telephone: +44 (0) 1670
04.21
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Vitreous Enamelled
Wirewound Resistors
Vitreous Enamelled
W20 Series
Solvent Resistance
W20 Series
Wirewound Resistors
Welwyn Components
Flammability
The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits
Solvent Resistance
Flammability
The body protection and marking are resistant to all normal
All materials used in the construction of ‘W’ series resistors
are inorganic and inherently non burning.
industrial cleaning solvents suitable for printed circuits.
All materials used in the construction of W20 series resistors are inorganic and inherently non-burning.
Performance Data
CECC 40201-002
IECQ-CECC 40201-002
Requirements
Load at commercial rating: 1000 hrs at 25°C
R%
Load at CECC rating: 1000 hours at 25°C
R%
5
Dry heat: 1000 hours at 200°C
R%
5
Shelf life: 12 months at room temperature
R%
not specified
Derating
Short term overload
R%
1
Climatic
R%
5
Climatic category
R%
55/200/56
R%
5
0.05
0.02
Long term damp heat
Temperature rapid change
R%
1
0.5
0.2
Resistance to solder heat
R%
1
0.25
0.03
R%
1
0.25
0.05
Vibration and bump
Noise (in decade of frequency)
µv/v
not specified
zero
zero
Robustness
R%
1
0.4
0.05
Insulation resistance
ohms
not specified
> 1G ohm
> 1G ohm
Voltage Proof
volts
not specified
500 min
500 min
Pulse handling
data available by request
Data available at: https://www.ttelectronics.com/TTElectronics/media/ProductFiles/Resistors/ApplicationNotes/Wirewound-Pulse-Overload-Resistors.pdf
Actual Performance
Maximum
Typical
5
3.5
5
3.5
2
1
0.03
0.02
see derating curve
1.0
0.2
0.5
0.2
Application Notes
The termination should not be bent closer than 1.6mm from
the body, and the recommended minimum bend radius is
1.2mm. The terminations are solderable to within 4mm from
the body. When cold, vitreous enamel has excellent insulation
resistance. In common with all insulants the specific resistance
of the enamel decreases with increase in temperature.
Therefore, resistors operated at near maximum temperature
cannot be classed as insulated and should not be used in
contact with any conducting material. Care must be taken
when determining clearance distance between the resistor
body and the printed circuit board or other components to
ensure these are not over heated. Resistance is measured
6mm from body.
116
Packaging
For W21 the standard method of packaging is
taped in Ammo Packs. For W22 the standard method of
packaging is taped and reeled. W23’s and W24’s are
available only as loose packed in boxes.
10
f
1
6
f
1
– f
2
b
1.4 mm
f
2
6
Derating Curve
% of Rated Power
100
54
Type
W21
W22
25
70
200
315
b
63±2
73±2
0
Ambient temperature
General Note
°C
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
BI Technologies IRC Welwyn
www.ttelectronics.com/resistors
© TT Electronics plc
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
04.21
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Wirewound Resistors
W20 Series
W20 Series
Vitreous Enamelled
Vitreous Enamelled
Wirewound Resistors
Welwyn Components
Ordering Procedure
Example: W22 at 3.3 kilohms and 5%
Pb-free)
Example: W22-3K3JI
(W22, 3.3 kilohms ±5%,
tolerance on a reel of 700 pieces –
W
2
1
1
2
2
-
3
K
2
3
J
3
3
Tolerance
F = ±1%
G = ±2%
J = ±5%
I
4
4
Packing & Termination Finish
I = Standard packing & Pb-free
PB
*
= Standard packing & SnPb
W21
1000/box
W22
700/reel
W23, W24
50/box
W22–3K3J
I
Type
Value (use IEC62 code)
Type
W21
Value
Tolerance (use IEC62 code)
W22
R = ohms
F
G
1%
2%
J
W23
W24
5%
kilohms
K=
E24 = 3/4 characters
Packing
I
Ammo W21, W215
1000/box
For CECC released product state on order the CECC number and style. Example:
W22-3K3JI CECC40201-002 KB
W22-3K3JI IECQ-CECC40201-002 KB
* SnPb termination will be EOL from December 2021
Bulk
W23, W24
50/box
Tape
W22
700/reel
Standard
For CECC released product state on order the CECC number and style. Example:
W22-3K3JI CECC40201-002 KB
For SnPb finish instead of Pb-free replace the packing suffix with
PB.
Example:
W22-3K3JPB
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
All information is subject to TT Electronics’ 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
BI Technologies IRC Welwyn
07.11
www.ttelectronics.com/resistors
86
© TT Electronics plc
04.21
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