Electronics — Resistor Color Code Reference
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Electronics — Resistor Color Code Reference
Color Code Table
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | x1 | — |
| Brown | 1 | x10 | ±1% |
| Red | 2 | x100 | ±2% |
| Orange | 3 | x1K | — |
| Yellow | 4 | x10K | — |
| Green | 5 | x100K | ±0.5% |
| Blue | 6 | x1M | ±0.25% |
| Violet | 7 | x10M | ±0.1% |
| Gray | 8 | — | ±0.05% |
| White | 9 | — | — |
| Gold | — | x0.1 | ±5% |
| Silver | — | x0.01 | ±10% |
Reading a 4-Band Resistor
[1st digit] [2nd digit] [multiplier] [tolerance]
Example: Red Red Brown Gold = 2 2 x10 ±5% = 220Ω
Common Values
| Value | Bands |
|---|---|
| 10Ω | Brown Black Black Gold |
| 100Ω | Brown Black Brown Gold |
| 220Ω | Red Red Brown Gold |
| 470Ω | Yellow Violet Brown Gold |
| 1kΩ | Brown Black Red Gold |
| 10kΩ | Brown Black Orange Gold |
| 100kΩ | Brown Black Yellow Gold |
Ohm's Law
| Formula | Use |
|---|---|
| V = I x R | Find voltage |
| I = V / R | Find current |
| R = V / I | Find resistance |
| P = V x I | Find power (watts) |
LED Resistor Formula
R = (Vsupply - Vforward) / Idesired
Example: 5V, red LED (Vf=2V), 20mA → R = (5-2)/0.02 = 150Ω
Typical Vf: Red 2V, Yellow/Green 2.2V, Blue/White 3.2V