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Resistor color codes and calculations as a Java Maven library

2019-11-25 11:44:49
This is a Java library made and shared as preparation for my book-in-progress Getting started with Java on the Raspberry Pi.
The example applications using this library and a lot more info about Java and the Pi in the book!
You can already buy it on Leanpub and will receive all future updates!
Next step in my book progress, is getting more into the details of hardware components. And as always starting with the smallest most-used ones: resistors!
To be able to fully document this for the book and create a demo application, I started again with creating and sharing a Java library.

Maven repository

A first version is now available on Maven.



Source code

Similar to my other shared libraries, the sources are available on GitHub.

How to use

Resistor color coding


Available as ColorCode.BLACK, ColorCode.BROWN... and includes all values listed in this table:

ColorCode HEX color Value Multiplier Tolerance (%) Temp. coeff. (ppm/K)
BLACK #000000 0 250
BROWN #761d1d 1 10Ω 1.0 100
RED #cc0000 2 100Ω 2.0 50
ORANGE #ffa500 3 1KΩ 15
YELLOW #ffff00 4 10KΩ 0.0 25
GREEN #008000 5 100KΩ 0.5 20
BLUE #0000cc 6 1MΩ 0.25 10
VIOLET #ee82ee 7 10MΩ 0.1 5
GREY #808080 8 100MΩ 0.25 1
WHITE #ffffff 9 1GΩ 0.0
GOLD #ffd700 0.1Ω 5.0
SILVER #c0c0c0 0.01Ω 10.0
NONE 20.0


Calculate value of a resistor based on 3, 4, 5 or 6 ColorCodes


Example with 3 ColorCodes
ColorValue value3band = Calculate.resistorValue(
        Arrays.asList(ColorCode.ORANGE, ColorCode.ORANGE, ColorCode.BROWN)
);
System.out.println(Convert.toOhmString(value3band.getOhm()));           // Result: 330Ω
System.out.println(value3band.getTolerance() + "%");                    // Result: 20.0%
Example with 6 ColorCodes
ColorValue value6band = Calculate.resistorValue(
        Arrays.asList(
                ColorCode.ORANGE, ColorCode.WHITE, ColorCode.BLACK,
                ColorCode.SILVER, ColorCode.BROWN, ColorCode.RED
        )
);

System.out.println(Convert.toOhmString(value6band.getOhm()));           // Result: 3.9Ω
System.out.println(value6band.getTolerance() + "%");                    // Result: 1.0%
System.out.println(value6band.getTemperatureCoefficient() + "ppm/K");   // Result: 50ppm/K

Calculate required resistor value for a LED

// Calculate.resistorForLed(double sourceVoltage, double ledVoltage, double ledCurrent)
System.out.println(Calculate.resistorForLed(3.3, 2.2, 0.02));           // Result: 55Ω

Calculate total value for resistors in serial or parallel

// Calculate.serial(List values) {
System.out.println(Calculate.serial(Arrays.asList(2D, 5D, 7D)));        // Result: 14Ω
    
// Calculate.parallel(List values)
System.out.println(Calculate.parallel(Arrays.asList(10D, 2D, 1D)));     // Result: 0.625Ω