4.7 kΩ resistor color code

Where you'll meet it

The data line of a DS18B20 temperature sensor

The DS18B20 sends its readings over a single data wire, called DQ. That wire is only ever pulled low, by the sensor or by the Arduino, so a 4.7 kΩ resistor from DQ to 5 V pulls it back up. Leave it out and the usual Arduino library reports −127 °C, its code for no sensor found.

I = 5 V / 4.7 kΩ ≈ 1.06 mA

That current flows only while the line is held low. The DS18B20 can sink 4 mA, so 1.06 mA is easy for it.

On a 3.3 V board, connect the resistor and the sensor's VDD to 3.3 V, not 5 V: then 3.3 V / 4.7 kΩ ≈ 0.7 mA flows and the sensor still works.

While the line is low the resistor turns 5 V × 1.06 mA ≈ 0.005 W into heat, so any size will do.

One resistor serves the whole line, even with several sensors on it. The drawing shows the normal three-wire hookup, with the sensor's VDD pin on 5 V. Very long cables can need a smaller resistor.

On SMD parts

Look for 472 or 4701

• 472472 = 47 × 10² = 4,700 Ω (3-digit code).
• 47014701 = 470 × 10¹ = 4,700 Ω (4-digit code, usually ±1% parts).

There is no EIA-96 code, because 4.7 kΩ is not an E96 value (the nearest E96 values are 4.64 kΩ and 4.75 kΩ).

Check it with a meter

Read 4.465–4.935 kΩ

1. Take the resistor out of the circuit.
2. Set the meter to Ω, range 20 kΩ (or auto).
3. Touch one probe to each lead. Keep your fingers off the metal: your body is a resistor too.
4. Anything from 4.465 to 4.935 kΩ is a good ±5% part. A 5-band ±1% part should read 4.653 to 4.747 kΩ.

A meter has a small error of its own, so a reading a hair outside the range does not prove the part is bad. Measure again with firm contact before you swap it.