The wirewound resistor

A more obvious way to get resistance is to use a length of wire that isn’t a good conductor. Nichrome is most often used for this. The wire can be wound around a cylindrical form, like a coil (Fig. 6-6). The resistance is determined by how well the wire metal conducts, by its diameter or gauge, and by its length. This component is called a wirewound resistor.

One of the advantages of wirewound resistors is that they can be made to have values within a very close range; that is, they are precision components. Another advantage is that wirewound resistors can be made to handle large amounts of power. Some wirewounds might actually do well as electric heaters, dissipating hundreds, or even thousands of watts.

A disadvantage of wirewound resistors, in some applications, is that they act like inductors. This makes them unsuitable for use in most radio-frequency circuits. Wirewound resistors usually have low to moderate values of resistance.