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LED series resistor calculator.

Power supply voltage Volts.
Forward voltage of LED Volts.
Forward current of LED mA.
Will require a series resistor of   Ω

How to use this page..

To use this page,
Ensure the list of resistors is correct for your collection.
You can populate the list with one of the buttons but any custom values added will be lost.
The list of resistors will be automatically saved on exit and restored when next used.
Once the resistor values are correct, enter the desired (parallel) value in the third column and press calculate to get a list of available combinations.
A list of values will then be displayed.
R1 and R2 are the two resistors to be paralleled.
Go on, guess what the other columns are!!
It is assumed that only 1 decade of values is required and anyone needing (for example) a 250Ω resistor will enter 25 as the desired value and use ten times the values for R1 and R2 (360 and 820).
Should there be a need to include other decades then the code could be modified to do so. Likewise, if it's thought necessary to add E48 values etc. then they can also be added.

List of resistors available.

Desired resistance Ω.