LED (Single) Circuit Power And Series Resistor Calculator
What resistor should I use with my LED? This calculator helps determine that for you. Enter the data required for Supply Battery Voltage in the range of 3 to 24 volts, the Diode Forward Voltage in the range of 2 to 4 volts, and the Diode Rated Current in the range of 10 to 50 milliamps (mA). Click on Calculate for the results which assume for power calculations, the use of the standard value current-limiting resistor indicated. This calculator rounds the resistance up to the next standard resistor value. You should actually be able to buy a common 5% resistor with the value returned by the calculator. For identification purposes, the negative side of the LED is the flat side and the shorter lead, which is called the cathode. The positive side is called the anode. Anode ----|>|---- Cathode
Unit
Number
Required Data Entry
Supply Battery Voltage Volts
Diode Forward Voltage Volts
Diode Rated Current milliamps (mA)
   
Calculated Results
Calculated Resistance Value Ohms
Next Standard 5% Resistor * Ohms
Resistor Color Markings 5%
Power Dissipated In LED milliwatts (mW)
Power Dissipated In Resistor milliwatts (mW)