Scratch on Raspberry Pi
"Design Challenge - Remix Jetpack Girl" by ScratchEdTeam is licensed under CC BY 2.0
Scratch is a visual programming tool which allows the user to create animations and games with a drag-and-drop interface. It allows you to create your own computer games, interactive stories, and animations using some programming techniques without actually having to write code. It’s a great way to get started programming on the Raspberry Pi with young people.
The version of Scratch included with the Raspberry Pi has a number of unique features; one of the most useful is its ability to communicate with the GPIO pins (General Purpose Input Output). These pins allow you to connect your Raspberry Pi to a range of devices, from lights and motors to buttons and sensors.
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Essential Raspberry Pi accessories
Essential accessories to get started with Raspberry Pi.
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Power Supply
To connect to a power socket, all Raspberry Pi models have a USB port (the same found on many mobile phones): either USB-C for Raspberry Pi 4, or micro USB for Raspberry Pi 3, 2 and 1.
MicroSD card
Your Raspberry Pi needs an SD card to store all its files and the Raspbian operating system.
A keyboard and a mouse
To start using your Raspberry Pi, you need a USB keyboard and a USB mouse.
A TV or computer screen
To view the Raspbian desktop environment, you need a screen, and a cable to link the screen and the Pi.
HDMI
The Raspberry Pi has a HDMI output port that is compatible with the HDMI port of most modern TVs and computer monitors.
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What is Raspberry Pi?
The Raspberry Pi is a low cost, credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. It is a capable little device that enables people of all ages to explore computing, and to learn how to program in languages like Scratch and Python. It’s capable of doing everything you’d expect a desktop computer to do, from browsing the internet and playing high-definition video, to making spreadsheets, word-processing, and playing games.
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The Raspberry Pi operates in the open source ecosystem: it runs Linux (a variety of distributions), and its main supported operating system, Raspberry Pi OS (formerly Raspbian), is open source and runs a suite of open source software. The Raspberry Pi Foundation contributes to the Linux kernel and various other open source projects as well as releasing much of its own software as open source.
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CSS Style Guides
CSS style guides are a group of documents that outline the coding style, best practices, and visual design properties (e.g. colors, layout grid dimensions, etc.) of a site. The goal of having a style guide is to maintain consistency across a product.
Below is a sample list of CSS Style Guides available on the internet,
Airbnb CSS / Sass Styleguide
Github Style Guide
https://styleguide.github.com/
Wordpress CSS Coding Standards
https://make.wordpress.org/core/handbook/best-practices/coding-standards/css/
Google HTML/CSS Style Guide
https://google.github.io/styleguide/htmlcssguide.html
Bootstrap CSS Code Guide
Lonley Planet CSS Code Guide
https://rizzo.lonelyplanet.com/documentation/css/naming
ThinkUp CSS Code Guide
https://github.com/ThinkUpLLC/ThinkUp/wiki/Code-Style-Guide:-CSS
Idiomatic CSS
https://github.com/necolas/idiomatic-css
CSS Guidlines
CSS Style Guide
https://www.smashingmagazine.com/2008/05/improving-code-readability-with-css-styleguides/
jQuery CSS Style Guide
https://contribute.jquery.org/style-guide/css/
BEM
http://getbem.com/introduction/
Atomic CSS
Object-Oriented CSS
Suit CSS
SendGrid Style Guide
https://styleguide.sendgrid.com/
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What is a Transistor?
"Various Electronic Components" by mercadoviagens.com is licensed under CC BY 2.0
A transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch.
When it works as an amplifier, it takes in a tiny electric current at one end (an input current) and produces a much bigger electric current (an output current) at the other. In other words, it’s a kind of current booster.
Transistors can also work as switches. A tiny electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. In other words, the small current switches on the larger one. This is essentially how all computer chips work.
Generally transistor is made of solid material which contains three terminals such as emitter (E), Base (B) and Collector (C) for connections with other components in the circuit.
There are two main types of transistors-junction transistors and field effect transistors.
JUNCTION TRANSISTORS
A junction transistor consists of a thin piece of one type of semiconductor material between two thicker layers of the opposite type. For example, if the middle layer is p-type, the outside layers must be n-type. Such a transistor is an NPN transistor. One of the outside layers is called the emitter, and the other is known as the collector. The middle layer is the base. The places where the emitter joins the base and the base joins the collector are called junctions.
FIELD EFFECT TRANSISTORS
A field effect transistor has only two layers of semiconductor material, one on top of the other. Electricity flows through one of the layers, called the channel. A voltage connected to the other layer, called the gate, interferes with the current flowing in the channel. Thus, the voltage connected to the gate controls the strength of the current in the channel.