The Arduino Uno is a microcontroller board based on the ATmega328. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega16U programmed as a USB-to-serial converter.
Features:

1. digital I/O pins: 14 (of which 6 provide PWM output)
2. analogue input pins: 6
3. contains: 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button

Specifications:

1. power supply: 6-20 V max. (adapter not included)
2. microcontroller: ATmega328p SMD
3. digital I/O pins: 14 (of which 6 provide PWM output)
4. DC current per I/O pin: 20 mA
5. DC current for 3.3 V pin: 50 mA
6. analogue input pins: 6
7. flash memory: 32 kB (ATmega328P) of which 0.5 kB used by bootloader
8. SRAM: 2 kB (ATmega328P)
9. EEPROM: 1 kB (ATmega328P)
10. clock speed: 16 MHz

resistor_colour_code.pdf

module_diy_kit_guide.pdf