Nearest E24 Resistor Value

Formula

Description

The E24 series defines 24 standard resistor values per decade, corresponding to 5% tolerance resistors. Values are geometrically spaced so that each value is approximately 10^(1/24) ≈ 1.101 times the previous one. When designing circuits, you must select from available standard values rather than arbitrary computed values. This formula finds the nearest E24 value to any target resistance. Other standard series include E12 (10%), E48 (2%), E96 (1%), and E192 (0.5%).

Variables

• R — Target resistance value (Ω)

Practical Notes

The E24 series values per decade are: 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, 9.1. For tighter tolerance designs, use E96 or E192 series which provide finer granularity. The output is the nearest standard value in the same decade as the input.