If you like to build electronics projects, with Arduino, Raspberry Pi or with ESP8266 based boards this YouTube channel is for you.
Arduino
Arduino: What DC Adapter Do I Use?
The short answer is: 9 to 12V DC, 250mA or more, 2.1mm plug, center pin positive. Ideally, you’ll want at least 500mA (1/2 amp) – 1000 mA (1 amp) and can run up to a 20V DC.