Wirewound

Wirewound refers to a type of resistor in which the resistive element is formed by winding a resistive alloy wire around a former or core. Common winding materials include nichrome, manganin, constantan, and other alloys chosen for their stable resistivity and temperature characteristics. The wound wire is typically secured to a ceramic or fiberglass core and then encapsulated in a protective coating such as ceramic, cement, or vitreous enamel. Terminal leads are attached to the ends of the winding, producing a compact, robust high‑power component.

Construction variants include non-inductive versions, in which the winding is arranged to cancel inductance (for example, bifilar or opposing windings) to reduce reactance in AC or RF circuits. Wirewound resistors are manufactured in several form factors, from small axial devices to large cement-coated power resistors and chassis-mounted components. Power ratings can range from a few watts to several kilowatts, with resistance values spanning milliohms to tens of ohms, depending on the alloy and geometry. Tolerances are commonly in the range of a fraction of a percent to several percent, and the temperature coefficient depends on the chosen alloy.

Applications emphasize high power dissipation, robust construction, and stable resistance under load. Wirewound resistors are widely used as power resistors, ballast resistors, dummy loads for testing, current sense elements, and snubbers in power supplies and industrial equipment. They are valued for their durability and heat handling but can exhibit significant inductance in their standard form, making non-inductive variants preferable in sensitive high-frequency or audio applications. Reliability is influenced by thermal cycling, mechanical stress, and environmental conditions.