resistance.js

<a href=""> <img alt="Logo" src="logo.png" width="500px"> </a> Simple module to calculate electrical resistance in series and parallel circuits. <a href="https://codeship.com/projects/136049"><img alt="Build Status" src="https://codeship.com/projects/ec5e9f90-bbe9-0133-6ce6-5a73e45d98be/status?branch=master"></a> <a href="https://travis-ci.org/mabrasil/resistance.js"><img alt="Build Status" src="https://travis-ci.org/mabrasil/resistance.js.svg?branch=master"></a> <a href="https://codeclimate.com/github/mabrasil/resistance.js"><img alt="Code Climate" src="https://codeclimate.com/github/mabrasil/resistance.js/badges/gpa.svg"/></a> <a href="https://david-dm.org/mabrasil/resistance.js" title="Dependency status"><img src="https://david-dm.org/mabrasil/resistance.js.svg"/></a> <a href="https://david-dm.org/mabrasil/resistance.js#info=devDependencies" title="devDependency status"><img src="https://david-dm.org/mabrasil/resistance.js/dev-status.svg"/></a> ## Table of Contents - [Installation](#installation) - [Usage](#usage) - [API](#api) - [Understand the Topic](#understand-the-topic) - [Development](#development) - [Contributing](#contributing) - [Motivation](#motivation) - [License](#license) - [Credits](#credits) ## Installation ```sh $ npm install --save resistance.js ``` ## Usage <a href=""> <img alt="Screenshot" src="http://i.imgur.com/SV3HhL7.png" width="900px"> </a> ```js const resistance = require('resistance.js'); resistance([1, 2, 3], 'series'); //=> 6 resistance([1, 2, 3], 'parallel'); //=> 0.5454545454545455 console.log(resistance([1, 2, 3], 'series') + 'Ω') // 6Ω ``` ## API ### `resistance(circuit, type)` #### `circuit` *Type*: `array` *Description*: Values of resistors associated in your circuit. *Example*: `[1, 2, 3, 4]` #### `type` *Type*: `string` *Description*: Type of resistors association in your circuit. *Options*: - `'series'` or `'s'`: Resistors in series. - `'parallel'` or `'p'`: Resistors in parallel. ## Understand the Topic Combinating resistors is very common in many circuits, when we want to reach a resistance level which only one resistor is not enough. ### Resistors in Series Let's take the following example: ![Series Example](http://i.imgur.com/qQ64hx7.gif) In an association of series resistors, the equivalent resistor is equal to the sum of all resistors that make up the association: ``` Req = R1 + R2 + R3 + R4 + ... ``` Also, the voltage in the electric generator is equal to the sum of all the voltages of resistors: ``` V = V1 + V2 + V3 + V4 + ... ``` The electric current flowing in each resistor is always the same: ``` i = i1 = i2 = i3 = i4 ... ``` And the initial example becomes: ![Final](http://i.imgur.com/wZxuZ3Q.gif) ### Resistors in Parallel Let's take the following example: ![Parallel Example](http://i.imgur.com/0eMK21o.gif) In an association of parallel resistors, the equivalent resistor is equal to the inverse of the sum of all the inverted resistors which make up the association: ``` 1 / Req = (1 / R1) + (1 / R2) + (1 / R3) + (1 / R4) + ... ``` Also, the current in the equivalent resistor is equal to the sum of currents from the resistors: ``` i = i1 + i2 + i3 + i4 + ... ``` The voltage in the electric generator is always the same: ``` V = V1 = V2 = V3 = V4 = ... ``` And the initial example becomes: ![Final](http://i.imgur.com/sEKnVFm.gif) ## Development All the tasks needed for development automation are defined in the [`package.json`](package.json) *scripts* property and can be run via: `npm run <command>` Here is a summary of all the commands: | **Command** | **Description** | |---------------|------------------------------------------------------------------------------------------| | `compile` | Runs the Livescript compiler on the source. | | `test` | Runs [Mocha](https://mochajs.org/) in BDD mode. | | `build` | Runs both `compile` and `test` commands. | ## Contributing Contributions are very welcome! If you'd like to contribute, these [guidelines](CONTRIBUTING.md) may help you. ## Motivation I was studying resistors association because of my *Constant Current* discipline and then decided to put the basics into practice. ## License [resistance.js](https://github.com/mabrasil/resistance.js) is distributed under the MIT License, available in this repository. All contributions are assumed to be also licensed under the MIT License. ## Credits Some contents used in the [explanation section](#understand-the-topic) were taken from [here](http://www.infoescola.com/fisica/associacao-de-resistores/).