wirewound resistor

This is also possible but less likely with metal film and wirewound resistors.

Tubular Wirewound Resistors are offered in large range of sizes.

Some wirewound resistors have coefficients of 10ppm/ C.

They are also used in low inductance wirewound resistors for use at RF frequencies.

If not enclosed, wirewound resistors can corrode.

The high frequency response of wirewound resistors is substantially worse than that of a composition resistor.

But I had to have them custom-made, as samples, from a wirewound resistor company in the US!)

Wirewound resistors are commonly made by winding a metal wire, usually nichrome, around a ceramic, plastic, or fiberglass core.

For higher power wirewound resistors, either a ceramic outer case or an aluminum outer case on top of an insulating layer is used.

Applications of wirewound resistors are similar to those of composition resistors with the exception of the high frequency.

Because wirewound resistors are coils they have more undesirable inductance than other types of resistor, although winding the wire in sections with alternately reversed direction can minimize inductance.

As discussed in section 2.3, wirewound resistors possess considerable inductance and capacitance and, where resistors are required in a.c. bridges, it is best to use modern thin-film types.

Earlier power wirewound resistors, such as brown vitreous-enameled types, however, were made with a different system of preferred values, such as some of those mentioned in the first sentence of this section.

The reason for the use of a line cord which is merely a wirewound resistor built into the mains lead is to get rid of surplus mains voltage so that the valves operate correctly.

These wirewound resistors are now used only in high-power applications, smaller resistors being cast from carbon composition (a mixture of carbon and filler) or fabricated as an insulating tube or chip coated with a metal film.

These resistors are designed to withstand unusually high temperatures of up to 450 C. Wire leads in low power wirewound resistors are usually between 0.6 and 0.8 mm in diameter and tinned for ease of soldering.

But it should be remembered that wirewound resistors are not available in true chip form (chip without a molding), and therefore are not usable in applications where weight and size limitations demand precision in the chip resistor format.