2.1 Ω resistor colour code
Five bands: Red · Brown · Black · Silver · Brown. The first three give the digits — a precision value needs all three — then the multiplier, then how far off the real part may be.
Nominal
2.1 Ω
2.1 ohms
Real range at ±1%
2.079 Ω – 2.121 Ω
A brown band allows this much drift.
Series
E96
A 1% precision value. Five bands, not four.
Band by band
| Band | Colour | Meaning |
|---|---|---|
| 1 | Red | 1st digit — 2 |
| 2 | Brown | 2nd digit — 1 |
| 3 | Black | 3rd digit — 0 |
| 4 | Silver | Multiplier — ×0.01 |
| 5 | Brown | Tolerance — ±1% |
How much it can take
Current and dissipation across the resistor, and the package you need. The suggested rating keeps a factor of two in hand, which is what anyone building a board actually does.
| Across it | Current | Dissipated | Package to pick |
|---|---|---|---|
| 3.3 V | 1.57 A | 5.19 W | no standard part — needs a power resistor or a heatsink |
| 5 V | 2.38 A | 11.9 W | no standard part — needs a power resistor or a heatsink |
| 12 V | 5.71 A | 68.6 W | no standard part — needs a power resistor or a heatsink |
| 24 V | 11.4 A | 274 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
27
683rd most of 1,465 values
In stock
0
across 0 of them
Cheapest at 100
$0.0078
each
Tolerances sold
±0.1% to ±1%
Packages: 1206, 0805, 0603, 1210, 2512, 0201, 0612, 2010. Ratings: 30mW to 2W.
Assembly stock from the JLCPCB library, read 2026-09-24. That is what a board house will place for you — not everything a distributor sells.
The same value, marked differently
Values that can overlap this one
At ±1% the tolerance bands of neighbouring values run into each other. A part sold as one of these could measure the same as a 2.1 Ω — which is why measuring beats reading when it matters.
If you do not have one
Standard values that land within 1% of 2.1 Ω when combined.