W31-2K7JI

Cement Coated Wirewound Resistors Welwyn Components W30 Series Values down to 10m ohms Tolerance to 1% Flameproof protection Custom built to meet pulse requirements Electrical Data W31 Notes Power rating at 25C watts 3.0 Power rating at 70C watts 2.5 Resistance range ohms 0R01 to 10K TCR (-55 to 155C) ppm/C See below Resistance tolerance % <R10: 5 >=R10: 1, 2, 5 Standard values E24 series preferred Other values to special order Thermal impedance C/watt 83 Ambient temperature range C -55 to 155 Limiting element voltage volts 100 TCR ppm/C 0.01 ohms <1000 0.033 ohms <500 0.091 ohms <200 10 ohms <150 10K ohms <100 Physical Data Maximum Dimensions (mm) and Weight (g) Type L max. D max. f min. d nom. Wt.nom. d D L W31 13 5.6 22.75 0.8 1.0 f Construction Marking A high quality ceramic substrate is assembled with W31 resistors are legend marked with type reference, interference fit end caps to which are welded the element resistance value and tolerance. Values are marked in winding and termination wires. The protection is then applied accordance with IEC 62. to the body, providing an effective seal which is impervious to moisture, shock, vibration, fungus and salt spray. Solvent Resistance The body and marking are resistant to all normal industrial Terminations cleaning solvents suitable for printed circuits. Material Solder coated copper. Strength The terminations meet the requirements of Flammability IEC 68.2.21. The resistor coating will not burn under any condition of Solderability The terminations meet the requirements of applied temperature or component overload. IEC 115-1, Clause 4.17.3.2. 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 D 07.06 99Cement Coated Wirewound Resistors Welwyn Components W30 Series Performance Data Maximum Typical Load: 1000 hrs 3 watts @ 25C R% 5.0 + .001 3.5 1000 hrs 2.5 watts @ 70C R% 5.0 + .001 3.5 Dry heat: 1000 hrs at 200C R% 5.0 + .001 3.5 Derating from room temperature see derating curve Short term overload 10 x rated power for 5 seconds R% 5.0 + .001 1.0 Climatic R% 5.0 + .001 3.5 Climatic category 55/200/56 Long term damp heat: 56 days R% 3.0 + .001 1.0 Temperature rapid change R% 2.0 + .001 1.5 Resistance to solder heat R% 5.0 + .001 2.0 Vibration and bump R% 5.0 + .001 2.0 Voltage proof volts 500 min Pulse handling Data available by request W31 Series Derating Curve 130 Application Notes 120 110 100 The terminations should not be bent closer than 1.6mm from 90 the body, and the recommended minimum bend radius is 80 1.2mm. 70 60 50 Care must be taken when determining clearance between the 40 resistor body and the P.C.B. or other components. Resistance 30 20 is measured 6mm from body. 10 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 Temp 10 Packaging The standard method of packaging is taped in ammo packs. Can be provided on reels by request. f f 1 2 W31 resistors can be supplied preformed. 6 63 6 Contact factory for details. f f 1.4 mm 1 2 Ordering Proced ure Example: W31 at 1 kilohms and 1% tolerance packed in a box of 1000 pieces W 3 1 1 K 0 F A 1 Type Value (use IEC62 code) Tolerance (use IEC62 code) F 1% G 2% J 5% Packing A1 Ammo 1000/box Standard T1 Tape 1000/reel 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 D 07.06 100 % of Rated Power at 70