LED current limiting resistor calculation

The calculator is an LED light-emitting diode current limiting resistor value calculator, which can calculate the LED current limiting resistance online.

How to calculate the current limiting resistance of LED led?

LED current limiting resistor calculation formula: current limiting resistor Ω = (supply voltage V - LED cut-in voltage V) / current limiting current A

Suppose you buy an LED with a cut-in voltage of 3.2V, a current-limiting current of 20mA, and a vehicle power supply voltage of 12V. The formula is (12V-3.2V) / 0.02A = 440.

If three resistors are connected in series, then the resistance value of each resistor is: (12V-3.2V*3) / 0.02A = 120Ω
And so on

 Single LED circuit Note: Different manufacturers, different color pressure drop is not the same. Red：2.0-2.2v Yellow：1.8-2.0v White：3.0-4v Blue：3.0-4v Green：2.0-2.2v 3.0-3.2v The above is for reference only. Voltage   V LED drop   V Required LED current   mA Calculating current limiting resistor   Ω Closest standard resistance   Calculate the resistance power   W Safe resistor power   W LED series circuit Voltage   V LED drop   V Required LED current   mA Number of connected LEDs   Calculating current limiting resistor   Ω Closest standard resistance   Calculate the resistance power   W Safe resistor power   W LED parallel circuit Voltage   V LED drop   V Required LED current   mA Number of connected LEDs   Calculating current limiting resistor   Ω Closest standard resistance   Calculate the resistance power   W Safe resistor power   W