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Resistor for a red LED on 12 volts

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510 Ω

resistor for a red LED on 12 V at 20 mA (calculated 500 Ω)

Red LED on 12 V by current

LED currentExact resistorStandard value
5 mA2,000 Ω2,000 Ω
10 mA1,000 Ω1,000 Ω
15 mA667 Ω680 Ω
20 mA500 Ω510 Ω

Assumes 2.0 V forward voltage; check your LED datasheet. One LED per resistor; for several LEDs in series subtract each forward voltage from the supply.

Other LED colors on 12 V

LEDForward voltageResistor @ 20 mA
Red2.0 V510 Ω
Yellow2.1 V510 Ω
Green2.2 V510 Ω
Blue3.2 V470 Ω
White3.2 V470 Ω

FAQ

What resistor for a red LED on 12V?

For a red LED (about 2.0 V forward voltage) at 20 mA on 12 V: R = (12 − 2.0) ÷ 0.020 = 500 Ω. The next standard value is 510 Ω, which gives 19.6 mA.

What resistor is safe for an Arduino or breadboard with a red LED on 12V?

A 1,000 Ω resistor limits the current to about 10 mA - dimmer but safe and long-lived. Use 510 Ω for full brightness.

What power rating does the resistor need?

At 19.6 mA it dissipates about 196 mW, so a 1/2 W resistor is enough.

LED resistor calculator · all supply voltages · Ohm’s law

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