IEC E-series lists are the standard resistor ladders used in catalogs. Manufacturers stock discrete values from these tables so you do not have to order arbitrary ohms.
E12, E24, and E96 at a glance
| Series | Typical tolerance | Values per decade | Common use |
|---|---|---|---|
| E12 | 10% | 12 | Legacy designs, coarse networks |
| E24 | 5% | 24 | General-purpose through-hole and many SMD lines |
| E96 | 1% | 96 | Precision dividers, instrumentation, tight ratios |
Each decade repeats the same mantissa pattern multiplied by 1, 10, 100, and so on. For example, in E24 the 1–10 range includes 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, and 9.1 Ω before the decade rolls to 10 Ω.
Picking a series in practice
Start from the target resistance your equation gives, then choose the nearest in-stock E24 value for 5% parts. If the error breaks a divider ratio or loop gain, step up to E96 1% values or combine two resistors in series or parallel using the parallel resistor calculator.
Power rating and package (see the SMD resistor category guide) are independent of the E-series label: a 1 kΩ E24 0402 part still follows the same numeric ladder as a through-hole 1 kΩ.