Resistor Color Code Values — Pick by Application (12 E24 Guides)
Choose the right E24 value guide by task: LED (120/220/330/470 Ω), RC timing (100 Ω), dividers (1 kΩ), I²C (2.2/4.7 kΩ), bias (47/100 kΩ), GPIO (10 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 |
|---|---|---|
| Bright 5 V LED / RS-485 termination | 120 Ω — bus termination & bright LED | Brown · Red · Brown · Gold |
| 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 |
| Fast I²C / capacitive bus | 2.2 kΩ — fast pull-up engineering | Red · Red · Red · Gold |
| GPIO / button pull-up | 10 kΩ — logic pulls | Brown · Black · Orange · Gold |
| Analog bias / 47 family | 47 kΩ — Y-V-orange family | Yellow · Violet · Orange · Gold |
| High-Z bias / divider top | 100 kΩ — megohm-range scaling | Brown · Black · Yellow · Gold |
| I²C / SMBus SDA,SCL default | 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 |
|---|---|---|
| 120 Ω | Brown · Red · Brown · Gold | RS-485 termination & bright LED |
| 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 |
| 2.2 kΩ | Red · Red · Red · Gold | fast I²C pull-ups & red-band trap |
| 10 kΩ | Brown · Black · Orange · Gold | button pull-ups & NTC dividers |
| 47 kΩ | Yellow · Violet · Orange · Gold | Y-V-orange 47 family & analog bias |
| 100 kΩ | Brown · Black · Yellow · Gold | high-Z biasing & divider top leg |
| 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
Topic cluster — calculator, hub & value guides
Every value guide below links back to this hub and to the color code calculator. Use the calculator to decode any physical part, then open the guide that matches your circuit (LED, I²C pull-up, divider, etc.). For the reading method, start with the beginner's guide or the calculator's 4-band section.
How these pages differ (avoid duplicate reading)
- 120 Ω — RS-485/CAN termination & high-current LED vs 220 Ω
- 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
- 2.2 kΩ — fast I²C when 4.7 kΩ fails (only fast-pull-up page)
- 10 kΩ — button pull-ups & NTC dividers
- 47 kΩ — full 47-family multiplier table & analog bias
- 100 kΩ — yellow/orange/green decade trap & high-Z dividers
- 4.7 kΩ — I²C rise time & bus capacitance (default I²C 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.
More tools
FAQ
How do I find the color code for a specific resistor value?
Pick your value from the application table above, open that guide for band colors and worked examples, or use the color code calculator to decode bands on a physical part.
What is the difference between 4-band and 5-band resistors?
4-band resistors use two digit bands plus multiplier and tolerance (typically ±5% gold). 5-band resistors add a third digit band for ±1% precision — common on 1 kΩ, 10 kΩ, and other E24 values in modern kits.
Which end of a resistor do you start reading from?
Start from the side where digit bands are grouped together. The tolerance band (gold, silver, or brown) sits on the opposite end. When in doubt, use the calculator to try both orientations.
How do you read a resistor color code step by step?
Identify digits (first 2 or 3 bands), read the multiplier band (adds zeros), then read tolerance. Example: Brown-Black-Red-Gold = 10 × 100 = 1 kΩ ±5%. See the beginner's guide for the full method.