Wiring ESP8266 WiFi Module for 3.3V

ESP8266, by default, operates on 3.3V and because of the same reason, care must be taken when connecting ESP8266 with any micro controller or Arduino boards which operates on TTL Level i.e. 0-5 volts.

If we drive ESP module through a power supply of 3.3 volts then the only remaining point of concern is the RX pin which will receive 5 volts  from Arduino or any other micro controller TX pin and will burn RX pin of ESP module eventually. Therefore it needs to be scaled down in the range of 0 – 3.3 volts.

Following circuit did exactly that.

ESP8266 wiring diagram

The TX pin of ESP module also works on 0-3.3 volts logic but we don’t need to scale it to 0-5 volts because in TTL logic 3.3 volt signal is already considered as HIGH logic therefore we can directly connect it to our micro controller RX pin.

We made a simple adaptor board to convert TTL logic into 3.3 volts using the above circuit diagram.



ESP8266 3.3v compatible adaptor

ESP8266 3.3v compatible adaptor with PL2303 USB to TTL Interface

Although Arduino has a 3.3 volt power pin on board but we should not drive ESP module from it because ESP module on average draws 130mA current which is quite a bit for Arduino board to provide and may damage the board eventually.

Sources to purchase ESP8266 and PL2303 Modues

ESP-01 ESP8266 2.4GHz Wireless Module – BLACK $2.69

Upgraded Version 1M Flash ESP8266 ESP-01 WIFI Transceiver Wireless Module $3.19

Check out variety of ESP8266 WiFi Module at Amazon


Buy PL2303 from Amazon – https://amzn.to/2uw8mof

Buy PL2303 from alternate source for $1.47

Checkout Amazon Store for PL2303


Note: PL2303 is not the only USB to TTL converter in the world, check out the following alternates, compare prices to make a decision when buying

– DIY CP2102 Chip USB to TTL Converter Module Board

– FT232RL FTDI USB to TTL Serial Adapter Module – RED

– MaiTech High Performance CH340 Chip USB to TTL Converter Module – BLACK

DIY USB to RS485 TTL Serial Converter Adapter for Arduino – BLACK

– MCU2012 CP2102 USB to TTL Converter Communication Module – BLUE


If you don’t have OR for some reason don’t want to use a 3.3v supply to power ESP module than you can modify the circuit and add a regulator to drive the ESP module (explained in detail in this article)

Absar A. Ansari


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