Read any resistor in seconds. Pick the number of bands and set each color — or flip to band-color mode and get the color code for a resistance value you already have. Works for 4-band, 5-band and 6-band resistors, with tolerance and temperature coefficient.
Read the bands from the end where they are grouped closest together; the tolerance band (usually gold or silver) sits on its own at the opposite end. Values follow IEC 60062. Tip: click a band on the resistor above to cycle its color.
A color-code chart tells you what a resistor is. It won't tell you why it's a pull-up, how to size a current-limiting resistor for an LED, or what an RC filter's cutoff frequency should be. Flux Copilot is the AI design partner that explains circuit architectures to you while you build — and picks real, in-stock parts.
R3 is LED1's current-limiting resistor, not a pull-up — it sets how much current the LED draws so the diode doesn't run away and cook itself.
That's plenty for an indicator and stays well inside the 20 mA the LED and your GPIO can handle. Want it brighter? 220 Ω gives roughly 14 mA — I can swap in an in-stock 0603 part and update the BOM.
What each color means in each band position (IEC 60062).
| Color | Digit | Multiplier | Tolerance | Temp. coef. (ppm/°C) |
|---|
