3R1

3R1 most commonly denotes a resistance value of 3.1 ohms in electronic resistor value notation. In this system, the letter 'R' stands for a decimal point, so 3R1 = 3.1 Ω. This marking is frequently seen on both axial through-hole resistors and surface-mount resistors, and it may appear alone or alongside tolerance indicators (for example, ±1% or ±5%) and power ratings (such as 1/4 W).

Outside resistor markings, 3R1 can appear as part of alphanumeric identifiers such as product codes, model numbers, or revision labels. In catalogs and components databases, 3R1 may designate a specific variant within a family, a manufacturing lot, or a deprecated part, depending on the issuing organization. Because it is a short, context-dependent string, its meaning is not universal and must be interpreted from surrounding data.

Overall, 3R1 is best understood as primarily a resistance value in electronics, with other uses as a generic identifier in non-electronic contexts.