SMD code 40R0 — 40 Ω
A surface-mount resistor has no bands. This one is a four-digit marking: the R is the decimal point — 40.0 Ω. Parts marked this way are usually ±1% or tighter.
40R0
reads as
40 Ω
Same value, other markings
40 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 | 625 mW | 2 W |
| 12 V | 3.6 W | no standard part — needs a power resistor or a heatsink |
What you can actually get
Parts made
3
at this value
Common packages
SMD,STANDOFF
Codes you will mistake it for
One character apart from 40R0. On a 0402 part these are a fraction of a millimetre of printing — worth a second look before you solder.