Ultra Precision Bulk Metal Film Resistors Welwyn Components 4800 Series • BS/CECC approved • Tolerances down to 0.005% • Current noise and distortion below level • • • • of practible measurement Low thermal e.m.f Ideal resistor for precision instrumentation Use of bulk metal gives superior stability Planar construction gives low residual capacitance and inductance Electrical Data Commercial 4802/12/32 4804 4805 Power Rating at 20°C watts 0.5 1 1.5 Resistance Range ohms 1R0 to 100K volts 200 350 500 5 5 5 Limiting element voltage TCR (20 to 70°C) ppm/°C 0R5 to 200K 33R0 to 300K Resistance tolerance See table 1 below Approved BS CECC 40-302-002* 4802/12 Power rating at 70°C watts 0.25 Resistance range ohms 100 to 56K volts 200 Limiting element voltage TCR (-55 to 125°C) ppm/°C 5 °C/watt 250 Resistance tolerance Thermal impedance See table 1 below Values Ambient temperature range Notes 130 80 E24 and E96 preferred Any value to order -55 to 155 All styles and products °C * BS CECC 40 Style reference: 4802 BX; 4812 CX Table 1. Resistance Range (ohms) and Tolerance (%) Tolerance (code) 4802/12/32 4804 4805 0.005 (E) 200R to 100K 100R to 200K 65R to 300K 0.01 (L) 100R to 100K 50R to 200K 33R to 300K 0.02 (P) 50R to 100K 25R to 200K 17R to 300K 0.05 (W) 25R to 100K 10R to 200K 8R to 300K 0.1 (B) 10R to 100K 5R to 200K 3.3R to 300K 0.25 (C) 5R to 100K 2R to 200K 1.7R to 300K 0.5 (D) 2R to 100K 10R to 200K 0.6R to 300K 1.0 (F) 1R to 100K 0.5R to 200K 0.33R to 300K 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 186 Issue B · 03.02 Ultra Precision Bulk Metal Film Resistors Welwyn Components 4800 series Physical Data Dimensions (mm) & Weight (g) Type L max H max W max T min d nom S nom Wt. nom 4802 8.9 10.2 3.8 30 0.6 5.1 1 4812 7.5 8 2.5 30 0.6 5.1 0.6 4802/12/04/05 L W H d dia T 4804 15.2 13.2 3.8 30 0.6 10.2 1.5 4805 22.6 13.2 3.8 30 0.6 17.8 2 4832 9.7 5.4 9.7 30 0.6 1.5 1.1 S 4832 d Construction Terminations The resistor element is an etched bulk metal foil, bonded to an alumina substrate. Connections to the foil are made by copper wires welded to the foil to minimise thermal e.m.f. Before encapsulation, the resistor element is coated with silicone rubber to isolate the element from mechanical stress which would adversely affect the carefully balanced construction and result in poor resistance/temperature characteristics. Material Strength H L W T S Solder coated copper wire The terminations meet the requirements of IEC 68.2.21. The terminations meet the requirements of IEC 115-1, Clause 4.17.3.2. Solderability Marking Type reference, resistance value, tolerance and date code are legend marked. The resistance value conforms to IEC 62. Solvent Resistance The protection will withstand all normal industrial solvents suitable for cleaning printed circuit boards. Performance Data Actual Load at commercial rating: 1000 hours at 70°C Dry heat: 1000 hours at 155°C Shelf life: 12 months at room temperature Derating from rated power at 70°C Short term overload Climatic category Climatic Long term damp heat Temperature rapid change Resistance to solder heat Vibration and bump Noise. (in a decade of frequency) Voltage coefficient of resistance Insulation Resistance Inductance Capacitance ∆R% ∆R% ∆R% Maximum 0.05 0.05 Typical 0.02 0.02 0.0025 Zero at 155°C ∆R% 0.01 0.005 55/155/56 ∆R% ∆R% ∆R% ∆R% ∆R% µV/V ppm/V ohms µH pF 0.05 0.05 0.01 0.01 0.01 0.03 0.03 0.005 0.005 0.005 Below level of practicable measurement >1000M 0.2 1 0.08 0.5 Packaging All components are supplied loose packed in either plastic bags or panel boxes. Quantity per box will depend on resistor size. © 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 B · 03.02 187