Pins Found on the Arduino Uno

The USB Input is the port we can use to program our Arduino board and to power it with 5 Volts. 

With this input, you can enable real-time communication with your computer and test your program.

The external power input is the port through which we can power our Arduino board with 5 to 20 volts. It is not highly recommended to supply less than 7 volts or more than 12 volts; to get the best performance, supply between 7 - 12 volts.

GND is what we can call the ground line, and when powering an external board attached to the Arduino, the negative pole is connected here.

These are the power pins we use to supply energy to an external board with Arduino; you can use any of these pins depending on the required energy.

These are the connection ports that allow Arduino to communicate with sensors.

There are only analog inputs on Arduino, and you cannot use them as analog outputs.

They are marked with a large A and receive values from 0 to 5; you can also connect inputs ranging from 0 to 5 Volts to these pins.

The Uno model of Arduino has 14 digital pins, and you can output 0 - 5 Volts from these digital pins.

Additionally, if you are going to use a Nextion screen, rather than using the TX and RX ports on the Arduino Uno model, it will be more efficient to designate any two digital pins as TX and RX pins and use them.

The digital pins with the "~" symbol can also be used as analog pins.

Aref pins are analog reference pins and are used for more sensitive applications.

The button you can use to restart the Arduino UNO.

Protects your device from currents that could damage it.