Precision Metal Film Resistors Provisional PR Series Low cost precision resistors Tolerances down to 0.1% TCR down to 15ppm/C Available with formed leads Electrical Data PR4 PR5 Power rating at 70C watts 0.25 0.5 Resistance range ohms 100 to 1M Limiting element voltage volts dc or ac peak 250 350 o o ppm/C 15, 25, 50 TCR (20 C 70 C) Resistance Tolerance % 0.1, 0.25, 0.5, 1 Standard Values E24, E96 Thermal Impedance 140 112 C/watt Ambient temperature range C -55 to +155 Table of Resistance Restrictions Tolerance % TCR ppm/C 0.1 0.25 0.5 1 15 100R 240K 25 100R 240K 100R 500K 100R 1M 50 General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. Issue D - 05.08 All information is subject to Welwyns own test data and is considered accurate at time of print. Welwyn Components Limited Welwyn Electronics Park, Bedlington, Northumberland, NE22 7AA, England. Tel: 01670 822181 Fax: 01670 829465 Web: www.welwyn-tt.com Physical Data Dimensions (mm) & Weight (g) PCB mount Min bend Type L max D max f min d nom Wt. nom centres radius 6.2 2.5 21 0.6 10.2 0.6 0.3 PR4 9.0 3.6 19.6 0.8 12.7 1.2 0.5 PR5 Construction Solvent Resistance The resistance element is a precisely controlled thin film of The body protection and marking are resistant to all normal metal alloy sputtered on to a high purity ceramic core, industrial cleaning solvents suitable for printed circuits. protected by a moisture-resistant, high dielectric strength coating applied so that terminations remain completely clear. Terminations This permits a well defined body length (clean lead to clean lead dimension L). Material: Solder-coated copper wire Strength: The terminations meet the requirements of Marking IEC 68.2.21 25ppm/C grade resistors are colour coded with 5 bands for Solderability: The terminations meet the requirements of th value and tolerance. For other grades a 6 band is added for the TCR. This is red for 50ppm/C and orange for 15ppm/C. IEC 62 colours are used. Performance Data Maximum 0.5 Load: 1000hrs at 70C R% Derating from rated power at 70C zero at 155C Short term overload 0.25 R% Climatic 0.5 R% Climatic category 55/125/56 Long term damp heat 0.5 R% Temperature rapid change 0.25 R% Resistance to solder heat 0.25 R% Vibration and bump 0.1 R% Insulation resistance ohms > 1G Voltage proof volts 700 min Packaging All PR resistors are supplied tape packed ready for loading on to automatic sequencing and insertion machines. 5mm Components wires will not protrude beyond the outside edge of the tapes. Alternative packaging is available by request. f1 f2 6 6 52mm Lead formed resistors can also be supplied. Standard options mm mm Body location f1-f2 < 1.4mm of Lancet, Radial and Goalpost forming are available. General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. All information is subject to Welwyns own test data and is considered accurate at time of print. Welwyn Components Limited Issue B 05.06 Welwyn Electronics Park, Bedlington, Northumberland, NE22 7AA, England. Tel: 01670 822181 Fax: 01670 829465 Web: www.welwyn-tt.com