Managing 5V->3.3V Voltage difference - Everything ESP8266 (2024)

FAQs

How do you reduce voltage from 5V to 3.3 V? ›

The easiest way to convert a 5V analog signal to a 3.3V analog signal is to use a resistor divider with an R1:R2 ratio of 1.7:3.3.

"The ESP8266 chip requires only 3.3V to communicate. The chip does not have 5V tolerant inputs. If the chip is connected to 5V devices, the chip might get damaged".

The ESP8266's maximum voltage is 3.6V, so the Thing has an onboard 3.3V regulator to deliver a safe, consistent voltage to the IC. That means the ESP8266's I/O pins also run at 3.3V, you'll need to level shift any 5V signals running into the IC.

According to the CEO of Espressif, Teo Swee Ann, the I/O pins of the ESP8266 are 5V tolerant.

It's called a “voltage divider.” In short, you pick a couple resistors and run current through, picking off the voltage at the point between the two resistors. The resistor values determine what that voltage will be. If the two resistors are the same, then you get half the voltage.

Simply use a voltage divider comprised of 2 resistors. One with twice the resistance of the other. You'll form a voltage divider which will output 2/3 of the voltage (3.3v on the point between the two resistors). Choose R2 to be twice as large as R1 (e.g. 10K + 20K ohms).

From the datasheet, we find nominal voltage of the esp8266 is 3.3V. Minimum voltage for stable operation is 2.5V and the maximum allowable limit is 3.6V. So for safely running an ESP8266 device, the battery voltage should be within 2.5 to 3.6V. An esp8266 chip can draw maximum 170mA current.

So the board works at 3.3v, your source maybe fluct between that but you will burn it if you apply 3.6 or more as a regular voltage. Usually ESP8266 modules have an onboard voltage regulator, USB connector and a pin labeled 5V. This pin or the USB cable certainly tolerate resp.

The Jaycar ESP8266 is a ESP-12N which has a 5V input to allow connection to a USB port. While the chips inside the module run at 3.3V. The ESP8266 processor definitely runs at 3.3V. The power pins are labelled on the board.

NodeMCU has a Vin pin that is connected to a voltage regulator (usually LD33). This regulator supports up to 15V as input (it also has a terrible dropout voltage). If you are supplying NodeMCU with >5V, then you can just use this pin and wire directly to the sensor.

How to power ESP8266 with 5V? ›

if you connect a 5V source to the 5V pin of the NodeMCU it should work as intended, as the 3.3V will be converted on the NodeMCU from 5V by the AMS1117 regulator on the unit.

The ESP8266 has a built in WiFi interface that supports 802.11 b/g/n 2.4 GHz networking. 5GHz frequencies are not supported.

Conceptually, put a 3.7 ohm & a 5–3.7 = 1.3 ohm resistor in series, with the 1.3 ohm resistor connected to the +5 V supply, and the 3.7 ohm resistor connected to ground (the - connection on the 5V supply). That will get you 3.7 V across the 3.7 ohm resistor.

A voltage divider is a simple circuit which turns a large voltage into a smaller one. Using just two series resistors and an input voltage, we can create an output voltage that is a fraction of the input. Voltage dividers are one of the most fundamental circuits in electronics.

With appropriate physical choice of component one only has to consider the voltage change required. If it is DC you need to drop, wire a 7.2volt zener diode in series with the supply. (19.2 - 12.0 = 7.2). It has to be the right way round.

The output voltage of a voltage converter is usually set via a resistor voltage divider. This works very well for fixed voltages. However, if the output voltage should be varied, one of the voltage divider's resistor values must be adjusted. This could be done dynamically with a potentiometer.