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 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 Approved BS CECC 40-201-002 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 Applicable to commercial and approved ranges Limiting element voltage Standard values Thermal impedance Ambient temperature range W21 3.0 1R to 10K 0R5 to 10K 0R1 to 10K W215 W22 W23 W24 5.0 7.0 10.0 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 10.0 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 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 Temperature Rise °C 400 W215 W21 W23 f min 22.75 23.1 23.1 - 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 W24 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. W22 300 Terminations 200 Material Strength Solderability Length 100 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 0 0 5 10 15 Dissipation – Watts 20 The resistors are legend marked with type reference, resistance value and tolerance. Values are marked in accordance with IEC 62. 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. A subsidiary of TT electronics plc © Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue C · 04.03 85 W20_C.qxd 28/4/03 10:19 am Page 2 Vitreous Enamelled Wirewound Resistors Welwyn Components W20 Series Solvent Resistance Flammability The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. All materials used in the construction of ‘W’ series resistors are inorganic and inherently non burning. Performance Data CECC 40201-002 Requirements Load at commercial rating: 1000 hrs at 25°c Load at CECC rating: 1000 hours at 25°c Dry heat: 1000 hours at 200°c Shelf life: 12 months at room temperature Derating Short term overload Climatic Climatic category Long term damp heat Temperature rapid change Resistance to solder heat Vibration and bump Noise (in decade of frequency) Robustness Insulation resistance Voltage Proof Pulse handling ∆R% ∆R% ∆R% ∆R% 5 5 not specified ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% ∆R% µv/v ∆R% ohms volts 1 5 55/200/56 5 1 1 1 not specified 1 not specified not specified Application Notes 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 0.05 0.02 0.5 0.2 0.25 0.03 0.25 0.05 zero zero 0.4 0.05 >.1G ohm >.1G ohm 500 min 500 min data available by request Packaging 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. For W21 and W215 the standard method of packaging is taped in Ammo Packs. For W22 the standard method of packaging is taped and reeled. Alternatives available by special request are detailed in the table below. W23’s and W24’s are available only as loose packed in boxes. W series resistors can be supplied preformed. Contact factory for details. 10 f1 6 Derating Curve % of Rated Power 116 f2 b f1 – f2 ≤ 1.4 mm 6 100 Standard Quantities Per Package Type Ammo pack Reel Small box 54 W21 1000 1000 n/a W215 750 750 n/a W22 500 700 n/a W23 n/a n/a 50 W24 n/a n/a 25 0 25 70 200 315 Ambient temperature °C Type b W21 63±2 W215 73±2 W22 73±2 © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 86 Issue C · 04.03