Using Atmel Atmega328P-AU MCU, Support ISP download; Support USB download and Power. it can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source It is a smallest, complete and breadboard friendly board. It has more analog input pins and on board +5V AREF jumper, compatible with Windows, Mac and Linux operating system. This board is using the chips ATmega328P and CH340, ,Support ISP download; Support USB download and Power. The nano has 8 analog inputs,each of which provide 10 bits of resolution.By default they measure from ground to 5 volts, though is it possible to change the upper end of their range using the analogReference function. Analog pins 6 and 7 cannot be used as digital pins, some pins have specialized functionality.