General Note
IRC reserves the right to make changes in product specification without notice or liability.
All information is subject to IRC’s own data and is considered accurate at time of going to print. A subsidiary of
TT electronics plc
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Vitreous Enamelled
Wirewound Resistors
Electrical Data
W20 Series
IRC
Type
Power Rating
@ 25°C
(watts)
Resistance
Range
(ohms)
Tolerance
(±%)
TCR
(-55°C to 200°C)
(±ppm/°C)
Limiting
Element
Voltage
(volts)
Thermal
Impedance*
(°C/watt)
Operating
Temperature
Range
(°C)
W21 3.0
1 - 10K 1 Typical: <+75
Maximum: +200 100 88 -55 to 3500.5 - 10K 2
0.1 - 10K 5
W215 5.0
1 - 15K 1 Typical: <+75
Maximum: +200 160 58 -55 to 3500.5 - 15K 2
0.1 - 15K 5
W22 7.0
1 - 20K 1 Typical: <+75
Maximum: +200 200 44 -55 to 3500.5 - 20K 2
0.1 - 20K 5
W23 10.0
1 - 60K 1 Typical: <+75
Maximum: +200 500 29 -55 to 3501 - 60K 2
0.15 - 60K 5
W24 14.0
1 - 100K 1 Typical: <+75
Maximum: +200 750 22 -55 to 3501 - 100K 2
0.2 - 100K 5
• High stability and reliability
• High purity ceramic substrate
• High power dissipation for size
• Suitable for harsh environments
• Rugged all-welded construction
• Impervious lead free vitreous enamel coating
• Overload characteristics ideal for protection circuits
*See temperature rise graph
W20 Series Issue December 2008 Sheet 1 of 4
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Vitreous Enamelled
Wirewound Resistors
Dimensions (mm) and Weight (g)
IRC 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 22.2 8.0 23.1 0.8 2
W23 38.0 8.0 --- 0.8 3.5
W24 53.5 8.0 --- 0.8 5
Physical Data
Lf
D
d dia.
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.
Length: W23’s and W24’s are not supplied on tape. Minimum length is 30mm.
MARKING
The resistors are legend marked with type reference, resistance value and tolerance.
SOLVENT RESISTANCE
The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed
circuits.
W20 Series Issue December 2008 Sheet 2 of 4
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
APPLICATION NOTES
The terminations should not be bent closer than 1.6mm from the body, and the recommended minimum bend
radius is 1.2 mm. Terminations are solderable to within 4mm from the body.
When cold, vitreous enamel has excellent insulation resistance. In common with all insulations the specific re-
sistance 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 printed circuit board or
other components to ensure these are not overheated. Resistance is measured 6mm from the resistor body.
Environmental Data
Test Actual Performance
Maximum Typical
Load at Commercial Rating: 1000 Hours @ room temperature 5 3.5
Dry Heat: 1000 hours @ 200°C 2 1
Shelf Life: 12 months at room temperature 0.03 0.02
Short Term Overload .47 0.1
Climatic 0.5 0.2
Long Term Damp Heat 0.05 0.02
Temperature Rapid Change 0.5 0.2
Resistance to Solder Heat 0.25 0.03
Vibration and Bump 0.25 0.05
Noise (In a Decade of Frequency) zero zero
Robustness 0.4 0.05
Insulation Resistance >1 G ohm >1 G ohm
Voltage Proof 500 min 500 min
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
µV/V
∆R%
ohms
volts
Vitreous Enamelled
Wirewound Resistors
Temperature Rise Curve
W20 Series Issue December 2008 Sheet 3 of 4
W22
Dissipation (watts)
Temperature Rise (°C)
05 10 15 20
400
300
200
100
W215 W22 W23 W24
• 4222 South Staples Street • Corpus Christi Texas 78411 USA
Wire and Film Technologies Division
Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com
Vitreous Enamelled
Wirewound Resistors
For W21, W215, and W22 resistors the standard method of packaging is taped in ammo packs. Alternatives
available by special request are:
- Taped and reeled
- Loose packed in boxes (minimum lead length 30mm). W23’s and W24’s are available only as loose
packed in boxes.
Packaging
Ordering Data
Sample Part No.
IRC Type
Value
Tolerance Code
J = 5%, G = 2%, F = 1%
Packaging Details
W21 9K1 J A
Specify type, reference, etc. as indicated in this example of
W21, 0.1KΩ, 5%, taped and ammo packed.
b
f1
10 ± 0.5
66
f2
Body location: f1 - f2 ≤ 1.4mm
Type A
W21 63 ± 2
W215 73 ± 2
W22 73 ± 2
Standard Quantities Per Package
Type Code W21 W215 W22 W23 W24
Ammo Pack A 1000 600 500 --- ---
Reel R 1000 800 700 --- ---
Small Box SB 200 100 100 50 25
Large Box LB 800 500 300 --- ---
W20 Series Issue December 2008 Sheet 4 of 4
