10k Ohm Resistor Color Code — GPIO Buttons & Sensor Dividers

10 kΩ: the default “weak pull” value

Brown · Black · Orange · Gold → $10 × 1000$ = 10 kΩ. Orange is the ×1 k multiplier band — the main reason people misread 10 kΩ as 1 kΩ (red = ×100).

4-band: Brown · Black · Orange · Gold → 10 × 1,000 = 10 kΩ (±5%) · 5-band (±1%): Brown · Black · Black · Red · Brown → 100 × 100 = 10 kΩ (±1%)

This page covers GPIO, buttons, and sensors. For I²C bus engineering, use the 4.7 kΩ I²C guide instead.

Button input with internal pull-up disabled (external 10 kΩ)

Typical UNO/Nano wiring concept:

1. One side of switch → GPIO input
2. Other side → GND
3. 10 kΩ from GPIO → 5 V (or 3.3 V)

When open: GPIO reads HIGH (~5 V). When pressed: GPIO reads LOW. Idle current ≈ $5 V / 10 kΩ = 0.5 mA$ per button — acceptable for bench; use 100 kΩ for battery if speed allows.

NTC / light sensor divider (10 kΩ as top leg)

Many hobby thermistor circuits use 10 kΩ fixed + NTC to mid-scale the ADC:

• Fixed 10 kΩ (Brown-Black-Orange) is the reference leg
• NTC changes $R_{NTC}$ with temperature → midpoint voltage moves

Identify the fixed resistor by color before assuming “all blue-body parts are NTCs.”

Decision: 10 kΩ vs 4.7 kΩ vs 1 kΩ (where to go next)

Need	Value	Read
I²C / SMBus SDA,SCL	4.7 kΩ typical	4.7 kΩ I²C guide
Strong pull, fast edge	1 kΩ	1 kΩ divider/pull guide
Default GPIO, low idle current	10 kΩ	(this page)
LED on 5 V	220–330 Ω	220 Ω LED guide

Orange vs red multiplier (10 kΩ vs 1 kΩ)

Multiplier band	Color	Effect on “10” digits
×100	Red	10 × 100 = 1 kΩ
×1 k	Orange	10 × 1k = 10 kΩ

Under poor light, orange can look red — always meter suspicious pull-ups on salvaged boards.

FAQ

10k resistor color code?

Brown, Black, Orange, Gold.

Is 10 kΩ OK for I²C?

Sometimes on short 100 kHz buses; fast mode or long cables often need 4.7 kΩ or lower — see 4.7 kΩ page.

Related guides (different topics)

• 4.7 kΩ color code — I²C rise time & bus capacitance

• 1 kΩ color code — divider math & strong pull-ups

• 1 MΩ color code — megohm measurement & op-amp bias

• Values hub — pick by application

• How to read any resistor (method)

• Decode bands online