by Gabriel Rapetti and Inventable.eu
Enter the resistance value you wish to obtain, select the multiplier (just next to the value), then click the "CALC" button. The calculator will display the pair of resistors whose parallel will be the value closest to the value you enter. At the same time, will show the equivalent resulting value and a picture of the resistors to be used.
This program allows you to obtain the closest equivalent resistance to the desired value using only two resistors belonging to the E12 series connected in parallel. We have chosen the E12 series because it is by far the most used in electronics.
The values belonging to this series are: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68 and 82. Each one of these values (1st and 2nd digit or color band) multiplied by the 3rd digit or color band (the multiplier) results in the entire range of values available in this series.
The option "always use two resistors" forces the calculator to use always two resistors, even if the result can be obtained with only one. This option is very useful if you need a standard value, but you don't have it available.
The equivalent value of two resistors connected in parallel can be calculated using one of the following formula:
This work is original and is licensed under a Creative Commons BY-NC-ND license. Creative Commons BY-NC-ND