## 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