LED Resistor Calculator

I believe this calculator to be accurate, but I assume no responsibilities or lilabilities for any errors that may occur in the use of this program!


This LED Resistor Calculator may also be used to calculate series resistors that are required for Zeners Diodes or a Standard Diode that is being Foreward biased and used like a Zener.

This calculator should determine the necessary resistor and wattage values for you.

If more than one LED or diode is used in a series string,  Add up all the "Foreward Voltages Drops" and enter this "Total Voltage".

D1 D2 D3

| /| | /| | /| Resistor Supply

___|/ |_____|/ |______|/ |______/\ /\ /\ /\ _______

V- |\ | |\ | |\ | \/ \/ \/ \/ V+

| \| | \| | \|



Enter Supply voltage Volts     [2-160 V]
Enter Diodes forward voltage Volts     [.5-159 V]
Enter Diodes rated current ma.       [2-50 ma]
Click Here to Calculate the:
Calculated resistance value Ohms
Next standard 5% resistor * Ohms
Resistor color markings
Power dissipated in LED('s) mw (if the exact calculated resistance value is used)
Power dissipated in resistor mw (Note: Your resistor wattage must exceed this value)

Copyright by Chemelec

Copyright © Jan/2003