Passiv Devices, Issue 01/08
CARBON TECHNOLOGY FROM TYCO!
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TYCO’s new and improved CBT-series resistors are ideal for circuit protection applications! Recently introduced by TYCO ELECTRONICS, the improved CBT resistor versions feature exceptional pulse withstanding capabilities. The resistors thus provide outstanding stability in applications associated with current surges, high peak power or energy pulses. With their advanced electrical characteristics, achieved by careful selection of materials and new developments in the manufacturing process, the highly reliable CBT25 (0.25W) and CBT50 (0.5W) are ideal for protecting circuits against lightning strikes. The cost-effective, high-performance CBT25 (maximum voltage: 250V) and CBT50 (maximum voltage: 350V) resistors are constructed utilizing a solid carbon composition that is best suited for absorbing high energy pulses. Intended as a direct replacement for traditional carbon-layer and wire resistors, CBT series resistors offer a much higher pulse handling capability because the entire rod conducts. In case of a fast (<100ms) high-energy pulse, a resistor’s conductive element is required to withstand all of the energy and absorb all of the heat generated. This is because it takes a given amount of time for the heat to flow from the conductive element to the surrounding material, and then to the ambient air. In layer and wire resistors, the layer or wire, respectively, must dissipate the energy pulse. However, because the layer or wire has only a limited mass, such resistors will correspondingly dissipate a limited amount of energy. The new solid-carbon resistors, on the other hand, have a significantly higher thermal mass and can thus dissipate more energy. Additional advantages of TYCO’s improved CBT series include the resistors’ compact size, the availability of a range of tolerances and wide range of resistive values (1R0 to 5M6 for the CBT25, and 1R0 to 22M for the CBT50), and the wide operating temperature range of
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