Overview
The datasheet presents information on the W20 Series of Vitreous Enamelled Wirewound Resistors manufactured by TTelectronics Welwyn Components. These resistors are designed for harsh environments and are CECC approved. They exhibit high stability, reliability, and power dissipation relative to their size, making them suitable for protection circuits.
Electrical Data
The resistors are available in multiple styles with power ratings ranging from 2.5 to 14.0 watts at 25°C. The resistance values span from 0.1 ohms to 100 kilohms with tolerances of 2% and 5%. The temperature coefficient of resistance (TCR) varies between +75 to +400 ppm/°C depending on the resistance range and style. Their limiting element voltage varies between 160 and 750 volts. The datasheet also specifies the overload characteristics and preferred values according to the E24 series, which can be ordered to specification.
Physical and Construction Details
Constructed on a high purity ceramic substrate, the resistors employ interference fit end caps with welded termination wires. The protective vitreous enamel coating that encapsulates the resistive element ensures durability and longevity. The terminations are copper-clad steel wire, nickel-plated, and solder-coated adhering to IEC standards.
Performance Data and Compliance
The resistors meet the CECC 40201-002 requirements for dry heat, load life, temperature rapid change, vibration, and more. They demonstrate a maximum typical load at CECC rating: 1000 hours at 25°C with an ∆R% of 0.5 and show robustness in a wide range of test scenarios showing insulation resistance of greater than 10^6 ohms.
Application Notes and Packaging
For optimal application, the datasheet provides guidance on bending the termination, derating curve advice, and caution regarding insulation resistance at high temperatures. Packaging options include Ammo Packs and reels for different component types, with quantities per package specified for standard orders.
Company Information
Welwyn Components, a subsidiary of TT electronics plc, is responsible for the manufacture of the W20 Series resistors. Contact information for their office in Bedlington, Northumberland, UK, is provided, including telephone, facsimile, and email details.
General Notes
The datasheet issues a general note stating that Welwyn Components reserves the right to make changes to product specifications without notice and emphasizes that the information is considered accurate at the time of publication.
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