standardresistorer

Standardresistorer, or standard resistors, are fixed-value passive components used to introduce a precise electrical resistance in circuits. They come in a wide range of resistance values, tolerances, power ratings, and package styles, and are found in both through-hole and surface-mount formats.

The values of standard resistors are organized into series known as E-series. Common series include E12, E24, E48, E96 and E192, each providing a defined set of preferred values per decade. For example, the E12 series uses 12 values per decade, such as 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, and 8.2, which are multiplied by powers of ten to cover a wide resistance range. Tolerance is separate from the value series and describes how closely a manufactured resistor matches its nominal value; common tolerances include ±1%, ±2%, ±5%, and ±10%.

Resistors are available in various power ratings, with typical through-hole parts offered in 1/8 W, 1/4 W, 1/2 W, 1 W and higher, while surface-mount devices cover a range from milliwatts up to several watts in compact packages. They also differ in construction, including carbon film, metal film, metal oxide, carbon composition, and, for SMD, thick- or thin-film technologies.

Marking methods vary: through-hole resistors are often labeled by color bands indicating value and tolerance, while SMD resistors carry printed numerical codes. Standard resistors are used for signaling, biasing, voltage division, and impedance matching across countless electronic applications. International standards, such as those defining the E-series under IEC guidelines, govern recommended values and nomenclature.