Volt voltage Ub
Volt LED voltage Uf
mA LED current If
N number of ( serial ) leds
°C temperature Tamb
°C/mW resistor Rth r-a
LED resistor	Ohm				E24 R
LED resistor	Ohm				E24 R
LED resistor	mW				E24 R
LED resistor	°C				E24 R
LED current	mA				E24 R
LED dissipation	mW				E24 R
Total dissipation	mW				E24 R
recommended	N max				E24 R
E24 series : 10 11 12 13 15 16 18 20 22 24 27 30 33 36 39 43 47 51 56 62 68 75 82 91.
colour code --

This script calculates the value of the LED resistor ( and the E24 equivalent, colour code included ) : the required serial resistor with one LED or more LEDS in a chain

1 - Type the available voltage Ub.

2 - Type the characteristic LED voltage Uled, Uf : according to the datasheet.

3 - Idem for the LED current Iled, If.

4 - ( A ) Give in the number of LEDS if you want place more.
     ( B ) Give in ( if you want this ) the temperature Tamb and the resistor Rth r-a ( Rth c-a, thermal resistance ) if it is known.

For example : Ub = 10 Volt, LED voltage = 2 Volt, LED current = 15 mA, 2 serial LEDS => you find the correct E24 value and the colour code.

5 - ( A ) You find a value in Ohm : the calculated serial resistor.
     ( B ) You find a value in Ohm : the E24 version. It can be equal to the value of the first resistor. Or it will be rounded up.
     ( C ) You find the E24 resistor and LED diode values of current and dissipation. Also total dissipation ( concerning the resistor and all the LEDS ) is given. Of course this JS calculates via the E24 resistor value ( E24 R ) ..... if this is unwanted, see here ( recommended ).

This is the simple basic formula, concerning the calculation of the serial resistor R = ( Ub - Uf ) / If

6 - The Reset System button clears the outputs and sets defaults again.