Engineering Masterclass
Resistor Color Code Values — Pick by Application (8 E24 Guides)
Choose the right E24 value guide by task: LED (220/330/470 Ω), RC timing (100 Ω), dividers (1 kΩ), GPIO (10 kΩ), I²C (4.7 kΩ), megohm (1 MΩ). Each page covers a different topic.
Pick a value, then verify in the calculator
Pick by application — not by memorizing every band
Each linked guide covers a different engineering topic. This hub does not repeat those tutorials — it routes you to the right one.
| Your task | Start here | Color-code deep dive |
|---|---|---|
| LED on 5 V / GPIO | 220 Ω — LED brightness vs 330/470 | Red · Red · Brown · Gold |
| LED on 3.3 V / Arduino vs ESP | 330 Ω — supply voltage matrix | Orange · Orange · Brown · Gold |
| Legacy dim 5 V LED | 470 Ω — textbook history | Yellow · Violet · Brown · Gold |
| RC timing / power at 100 Ω | 100 Ω — τ table & wattage | Brown · Black · Brown · Gold |
| Voltage divider / strong pull | 1 kΩ — divider math | Brown · Black · Red · Gold |
| GPIO / button pull-up | 10 kΩ — logic pulls | Brown · Black · Orange · Gold |
| I²C / SMBus SDA,SCL | 4.7 kΩ — bus rise time | Yellow · Violet · Red · Gold |
| Megohm / high-Z / timers | 1 MΩ — measurement guide | Brown · Black · Green · Gold |
Compact color reference (E24 values we document)
| Value | 4-band (±5%) | Unique guide focus |
|---|---|---|
| 220 Ω | Red · Red · Brown · Gold | LED brightness vs 330/470 Ω on 5 V |
| 100 Ω | Brown · Black · Brown · Gold | RC τ table & wattage at 12 V |
| 1 kΩ | Brown · Black · Red · Gold | divider math & strong pull-ups |
| 10 kΩ | Brown · Black · Orange · Gold | button pull-ups & NTC dividers |
| 470 Ω | Yellow · Violet · Brown · Gold | textbook LED history & Y-V family |
| 330 Ω | Orange · Orange · Brown · Gold | 5 V vs 3.3 V supply matrix |
| 4.7 kΩ | Yellow · Violet · Red · Gold | I²C rise time & bus capacitance |
| 1 MΩ | Brown · Black · Green · Gold | megohm measurement & op-amp bias |
Printable full IEC chart (all digits 0–9): Color Code Chart · Method: Beginner's Guide · Tool: Calculator
How these pages differ (avoid duplicate reading)
- 220 Ω — LED current comparison table (220/330/470)
- 330 Ω — 5 V vs 3.3 V supply matrix
- 470 Ω — historical “textbook LED” context
- 100 Ω — RC time constants & power dissipation
- 1 kΩ — voltage divider worked example
- 10 kΩ — button pull-ups & NTC dividers
- 4.7 kΩ — I²C rise time & bus capacitance (only I²C-focused page)
- 1 MΩ — megohm measurement protocol & high-Z errors
Reading one value page is enough for that value. Use this hub only to choose which page to open.
SMD parts
Chip resistors use 103 = 10 kΩ style codes, not bands — SMD decoder.