W20 C.qxd 28/4/03 10:19 am Page 1 Vitreous Enamelled Wirewound Resistors Welwyn Components W20 Series CECC approved Suitable for harsh environments Impervious lead free vitreous enamel coating Overload characteristics ideal for protection circuits High stability and reliability High power dissipation for size Electrical Data Commercial W21 W215 W22 W23 W24 Power rating at 25C watts 3.0 5.0 7.0 10.0 14.0 Resistance range at 1% tolerance ohms 1R to 10K 1R to 15K 1R to 22K 1R to 60K 1R to 100K 2% tolerance ohms 0R5 to 10K 0R5 to 15K 0R5 to 22K 1R to 60K 1R to 100K 5% tolerance ohms 0R1 to 10K 0R1 to 15K 0R1 to 22K 0R15 to 60K 0R2 to 100K TCR (-55 to 200C) pp/C Typically: <+-75 Maximum: +-200 Approved BS CECC 40-201-002 Style JB HB KB LB MB Power rating at 25C watts 2.9 5.0 7.0 10.0 14.0 Power rating at 70C watts 2.5 4.3 6.0 9.0 12.0 Resistance range at 1% tolerance ohms 1R to 10K 1R to 15K 1R to 20K 1R to 56K 1R to 100K 2% tolerance ohms 0R5 to 10K 0R5 to 15K 0R5 to 20K 1R to 56K 1R to 100K 5% tolerance ohms 0R1 to 10K 0R1 to 15K 0R1 to 20K 0R15 to 56K 0R2 to 100K TCR (-55 to 200C) 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) and 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 d W22 22.0 8.0 23.1 0.8 2 D L f W23 38.0 8.0 - 0.8 3.5 W24 53.5 8.0 - 0.8 5 400 Construction W21 W215 W23 W24 A high purity ceramic substrate is assembled with interference fit end caps to which are W22 welded the termination wires. The resistive element is wound on the substrate and welded to 300 the caps the vitreous enamel protective coating is then applied. Terminations 200 Material Copper clad steel wire, nickel plated and solder-coated. Strength The terminations meet the requirements of IEC 68.2.21. 100 Solderability The terminations meet the requirements of IEC 115-1, Clause 4.17.3.2. Length W23s and W24s are not supplied on tape. Minimum lead length is 30 mm. Marking 0 0 5 10 15 20 The resistors are legend marked with type reference, resistance value and tolerance. Values are marked in accordance with IEC 62. Dissipation Watts General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. A subsidiary of All information is subject to Welwyns own data and is considered accurate at time of going to print. TT electronics plc Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com Issue C 04.03 85 Temperature Rise CW20 C.qxd 28/4/03 10:19 am Page 2 Vitreous Enamelled Wirewound Resistors Welwyn Components W20 Series Flammability Solvent Resistance All materials used in the construction of W series resistors The body protection and marking are resistant to all normal are inorganic and inherently non burning. industrial cleaning solvents suitable for printed circuits. Performance Data CECC 40201-002 Actual Performance Requirements Maximum Typical Load at commercial rating: 1000 hrs at 25c R% 5 3.5 Load at CECC rating: 1000 hours at 25c R% 5 5 3.5 Dry heat: 1000 hours at 200c R% 5 2 1 Shelf life: 12 months at room temperature R% not specified 0.03 0.02 Derating see derating curve Short term overload R% 1 1.0 0.2 Climatic R% 5 0.5 0.2 Climatic category R% 55/200/56 Long term damp heat R% 5 0.05 0.02 Temperature rapid change R% 1 0.5 0.2 Resistance to solder heat R% 1 0.25 0.03 Vibration and bump R% 1 0.25 0.05 Noise (in decade of frequency) v/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 Application Notes Packaging The termination should not be bent closer than 1.6mm from For W21 and W215 the standard method of packaging is the body, and the recommended minimum bend radius is taped in Ammo Packs. For W22 the standard method of 1.2mm. The terminations are solderable to within 4mm from packaging is taped and reeled. Alternatives available by the body. When cold, vitreous enamel has excellent insulation special request are detailed in the table below. W23s and resistance. In common with all insulants the specific resistance W24s are available only as loose packed in boxes. W series of the enamel decreases with increase in temperature. resistors can be supplied preformed. Contact factory for Therefore, resistors operated at near maximum temperature details. cannot be classed as insulated and should not be used in contact with any conducting material. Care must be taken 10 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. f f 1 2 6 b 6 f f 1.4 mm 1 2 116 Derating Curve 100 54 Type b W21 632 W215 732 0 25 70 200 315 W22 732 Ambient temperature C Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com Issue C 04.03 86 % of Rated Power