I have seen this in several schematics which i assume are professional since they are for popular open-source products.
But i can't figure out why there is a 470 Ohms resistor in series between the RX pin of the Arduino and the TX pin of the ESP8266? Can someone please explain? Why choose this specific value since i see the same value resistor used in many schematics between the Arduino and the ESP8266?
I was also puzzling over the need for the potential divider but then i did some research and i found that there is a need for a logic-level shifter between the Arduino TX and the ESP8266 RX data line. But i can't find anything on the 470 Ohms series resistor.