Carbon composition resistors are used in applications where there are no stringent requirements for resistance tolerance, temperature stability or low noise. They are used where instantaneous surge currents are present since they are capable of safely handling sudden overloads of current and power for a short time. Carbon composition resistors (carbon comps) are components which use a mixture of carbon and fillers to form the resistive unit. These resistors are called hot molded units because the resistive material, the insulating material and lead wires are all molded at one time into a solid structure. Carbon composition resistors were the state-of-the art resistors during the early aviation and space days, but because of the loose tolerances and environmental vulnerability associated with carbon comps and the erosion of metal film prices, their popularity has decreased. The main use for carbon comps today is in existing designs.
Depositing carbon in film form onto a ceramic core creates carbon film resistors. Due to their low cost, carbon films are primarily used in general-purpose applications such as consumer products. Although they offer a slightly better temperature coefficient than carbon composition, they have a tendency to generate more noise.
Current sense resistors are used to monitor the current in a circuit and translate the amount of current in that circuit into a voltage that can be easily measured and monitored. This type of resistors generally have a low ohmic value, low EMF, high current capability, low inductance and have excellent frequency response.
Metal film resistors are composed of a resistive metal film deposited on, or inside of, an insulating cylinder or filament. Metal film resistors are used in all applications that require a tighter tolerance and temperature coefficient than is offered by carbon resistors. They are the most widely used resistors in today's marketplace because they are more precise than carbon comps at approximately the same price. There are three basic sizes for metal film resistors: 1/8 wattage package size, 1/4 wattage package size and 1/2 wattage package size.
Metal foil resistors are used in applications that require very precise resistance values that will not vary with temperature changes. Among the many unique characteristics of metal foil resistors are their extremely low temperature coefficients and their extremely low tolerances. Metal foil resistors are made by placing a very thin piece of metal onto a ceramic wafer, then photochemically etching a resistive pattern on the foil.
Metal oxide resistors are a type of power metal film resistor. They typically are specified for applications requiring 1 to 2 watts, though they are available up to 9 watts.
Resistor chip arrays are simply a group of flat chip resistors that are not separated. They are available in two package styles, concave and convex.
Resistor networks are a combination of resistors arranged and interconnected in a single package. The resistors can be arranged in series or parallel or a combination of the two. Network packaging variations are Single In-Line Package (SIP), Dual In-Line Package (DIP), flat pack, and surface mount. Resistor networks are available in two basic styles: thick film and thin film. The thick film network has gained acceptance as the preferred component.
Commercial chip resistors have become the "standard" resistor callout for new designs as the need for smaller components has become apparent. Resistor chips are manufactured using either "thick film" or "thin film" techniques. Thick film chips are made by specially formulated inks or pastes, which are silk-screened and fired onto a ceramic substrate. The chip is coated with a thin varnish or glaze. A "thin film" chip is manufactured by vacuum depositing a metal film onto a ceramic substrate. Thin film devices are more stable and precise than thick film, although the thick film is more common and can be rated at a higher wattage.
Wirewound resistors are made by winding high-resistance metal alloy wire around a ceramic core. Wirewound resistors are available up to 250 watts in standard application and can be fan-cooled or water-cooled in order to withstand even more power. Wirewound resistors are used for both high power applications, or where the need for ultra-precision resistors exists.
A resistor is a passive two-terminal electrical component to create resistance in the flow of electric current. Resistors have a variety of uses in electronic circuits, including to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines.
At TTI, we carry a wide selection of resistor types, such as Carbon Composition Resistors, Film Resistors, and Wirewound Resistors. Whether your industry requires automotive-grade or industrial, you can browse TTI to find the right resistor for your electronic design. We stock high-quality electronic components from trusted manufacturers like AVX, Nichicon, Panasonic, Vishay, Yageo and more.