SMD code 3R40 — 3.4 Ω
A surface-mount resistor has no bands. This one is a four-digit marking: the R is the decimal point — 3.40 Ω. Parts marked this way are usually ±1% or tighter.
3R40
reads as
3.4 Ω
The same part, in bands
The through-hole version of 3.4 Ω carries 5 colour bands instead.
Everything about 3.4 Ω — power ratings, what ten cost, what is in stock.
Same value, other markings
3.4 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 | 7.35 W | no standard part — needs a power resistor or a heatsink |
| 12 V | 42.4 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
22
at this value
Common packages
0603 · 1206 · 0805 · 1210
Codes you will mistake it for
One character apart from 3R40. On a 0402 part these are a fraction of a millimetre of printing — worth a second look before you solder.