SMD code 2R1 — 2.1 Ω
A surface-mount resistor has no bands. This one is a three-digit marking: the R is the decimal point — 2.1 Ω. Parts marked this way are usually ±5% or ±2%.
2R1
reads as
2.1 Ω
The same part, in bands
The through-hole version of 2.1 Ω carries 5 colour bands instead.
Everything about 2.1 Ω — power ratings, what ten cost, what is in stock.
Same value, other markings
2.1 Ω is printed several ways depending on the part's precision and size. A board can carry all of them at once.
How much it can take
| Across it | Dissipated | Smallest package that copes |
|---|---|---|
| 5 V | 11.9 W | no standard part — needs a power resistor or a heatsink |
| 12 V | 68.6 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
27
at this value
Common packages
1206 · 0805 · 0603 · 1210
Codes you will mistake it for
One character apart from 2R1. On a 0402 part these are a fraction of a millimetre of printing — worth a second look before you solder.