Arduino Power regulator gets hot

Hello all,

I have a project, where I use an Arduino UNO.

Currently the arduino is powered with 12V.

There are two components connected to the arduino which consume relatively much power.

It is.

a) ESP8266
b) MQ-8 hydrogen sensor

I have measured the ESP, it consumes about 80mA @ 3,3V (I have a 3,3 V voltage regulator)

I have calculated the MQ-8 sensor - it should consume around 180mA…

Somewhere I have read, that the maximum current that the voltage regulator of the arduino can deliver is Imax < 1W / (Vin - 5V)

Which in my case would be 142mA…

This would mean, that it could handle the ESP, however ESP + MQ-8 sensor is to much…

Is it possible, advisible to buy a 5V power supply and connect it directly to GND and 5V of the Arduino, in order to bypass the voltage regulator?

Is it better to buy a 6V power supply and use it with the voltage regulator.

If I use a 6V power supply the voltage regulator should be able to deliver up to 1A… This would be more than sufficient to run the ESP and the MQ-8…

Thanks for your Inpit.


6 volts is not enough to feed the on board 5V regulator. It needs 7V minimum. Use a converter to bring the 12V to 5V and feed to the 5V input. The 3.3V regulator on an Uno does not supply enough current (50mA) for an ESP8266. I always use a LM1117 3.3V regulator fed from 5V for my ESP projects. Don't forget the level shifters between the Uno and ESP inputs.

Hi groundFungus,

I do not use the 3,3V regulator from the arduino to feed the ESP.

I use this one:

It can deliver up to 800mA…

I just take the 5V from the arduino, to feed this voltage regulator.

Arduino + ESP works fine in this configuration… Only with the MQ8 sensor in addition things got hot and stinky…

Good to know I can’t feed the arduino with 6V…

Well, I think the best thing to do is to buy a standard 5V / 2A power supply and feed the power directly to the 5V pin and GND…