SMD code 3R90 — 3.9 Ω
A surface-mount resistor has no bands. This one is a four-digit marking: the R is the decimal point — 3.90 Ω. Parts marked this way are usually ±1% or tighter.
3R90
reads as
3.9 Ω
The same part, in bands
The through-hole version of 3.9 Ω carries 4 colour bands instead.
Everything about 3.9 Ω — power ratings, what ten cost, what is in stock.
Same value, other markings
3.9 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 | 6.41 W | no standard part — needs a power resistor or a heatsink |
| 12 V | 36.9 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
131
at this value
Ten pieces
$0.29
not the reel price
Common packages
0603 · 0805 · 1206 · 1210
Codes you will mistake it for
One character apart from 3R90. On a 0402 part these are a fraction of a millimetre of printing — worth a second look before you solder.