High Voltage Thick film Resistors Welwyn Components HV Series • • • • Resistance up to 250M Low temperature coefficient of resistance Working voltage up to 20kV Sets of resistors with matched characteristics Electrical Data HV31 HV32 HV33 HV34 HV35 Power rating at 70°C watts 0.5 0.75 1.0 1.25 1.5 Resistance range ohms 1K to 50M volts 1K 2K 4K 7K 10K In air 2K 4K 8K 14K 20K In oil Limiting element voltage TCR (20°C to 70°C) ppm/°C Resistance tolerance % Notes 1K to 100M 1K to 150M 1K to 200M 1K to 250M 50, 100 1, 2, 5 Values E24 preferred Thermal impedance °C/watt Ambient temperature range 75 70 °C Any value to special order 60 65 60 -55 to 155 Physical Data Dimensions (mm) & Weight (g) Type L max D max f min d nom PCB mounting centres Min. Bend Radius Wt. nom HV31 10.0 3.5 30.0 0.6 12.7 0.6 0.5 HV32 19.0 3.6 30.0 0.6 25.4 0.6 0.6 HV33 15.5 5.3 30.0 0.8 18.4 1.2 1.2 HV34 38.0 3.6 30.0 0.6 44.4 0.6 1.1 HV35 50.8 3.6 30.0 0.6 57.2 0.6 1.25 d D L f Construction Solvent Resistance A ruthenium oxide based resistive film is fired onto a high quality ceramic former. Brass caps are force fitted to the HV32, 34 and 35 rods and plated steel caps to the 31 and 33 sizes. The resistor is adjusted to value by a helical cut in the film, and the body is protected with a silicone coating. The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Marking Type reference, resistance value, tolerance and date code are legend marked. The resistance values conform to IEC 62. Terminations Material Solder coated copper wire. Strength The terminations meet the requirements of IEC 68.2.21. Solderability The terminations meet the requirements of 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. 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 B · 03.02 195 High Voltage Thick film Resistors Welwyn Components HV Series Performance Data Maximum Typical Load at rated power: 1000 hours at 70°C ∆R% 1 0.3 Shelf life: 12 months at room temperature ∆R% 0.3 0.1 Noise (in a decade of frequency) µV/V 5 <2.5 Voltage coefficient of resistance ppm/volt 5 <2 Derating from rated power at 70°C Zero at 155°C Matched Sets Resistors in a set can be supplied for use as precision voltage dividers matched for tolerance and TCR down to 0.5% and 10ppm/°C. ENQUIRIES ARE WELCOMED FOR SPECIAL RESISTORS AND SETS Application Notes Mounting Packaging Due to the high voltage which can appear between the end cap and any adjacent metal part, resistors should be mounted at an adequate distance from other conductors. Resistors are supplied packed in boxes. For some high voltage applications it is required to immerse the components in oil or gas to reduce the effects of corona and surface tracking. The protective coating is suitable for these applications. Standard Quantities Per Box All Types 10 or 20 per box The axial termination should not be bent closer than twice the diameter of the terminal wire from the body of the resistor. When the resistors are required to be potted, the preferred encapsulant is a silicone compound. For voltage dividers with a low resistance section below the minimum available value of 1k ohms, it is normal practice to use a Welwyn resistor, RC Series, obtainable down to 1ohm. © 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 196 Issue B · 03.02