Green Brown Black Gold — 51 Ω
Read left to right, starting from the end where the bands are grouped. The gold band is the tolerance and always sits alone at the far end.
What each band says
| Band | Colour | Meaning |
|---|---|---|
| 1 | Green | 1st digit — 5 |
| 2 | Brown | 2nd digit — 1 |
| 3 | Black | Multiplier — ×1 |
| 4 | Gold | Tolerance — ±5% |
In a circuit
Across 5 V
98 mA · 490 mW · 1 W part
Across 12 V
235 mA · 2.82 W · part
Surface-mount marking for the same value: 510.
If you misread one band
Brown and red, or orange and red, are easy to confuse under a desk lamp. These are the codes one band away from this one.