3.7v instead of 3.3v output on arduino nano

Hi,
I have got some chinese arduino nanos.

I measured 3.3 voltage and I have 3.7v instead.

At the moment, it is driving a nrf24l01 chip and voltage is a bit high.

How can I solve it , advices .
Thanks ,
S.Ancelot

What is supplying the Nano (USB, battery,..)?

powered with usb. There is an ams1117 chip that should make the conversion to 3.3v

What are you using to measure the 3.3 /3.7? Also measure the USB voltage with the same device and see if its near 5.0 Volts

sancelot:
powered with usb. There is an ams1117 chip that should make the conversion to 3.3v

No, there is not.

The Nano’s 3.3volt comes from the USB<>Serial chip (CH340).
Don’t know the curent capability, but it can deliver 30mA without collapsing (tried that).
Woudn’t go any higher than that.

I suspect the DMM is giving the wrong readings (flat battery?).
Do what JohnRob suggested, and see if the 5volt supply is also off.
Leo…

For powering external devices use an external voltage regulator.

jendalinda:
For powering external devices use an external voltage regulator.

Never used an nrf24l01, but I read they draw about 15mA max.
Why should you have to use an external 3.3volt supply for that.
Leo..

Wawa:
Never used an nrf24l01, but I read they draw about 15mA max.

That's only on an average, it needs more (peak) current while sending.

The ams1117 creates a 5 volt supply for the Nano when it is powered from the Vin pin. When powered by usb, the regulator does nothing.

The 3v3 supply is sourced by the CH340G/FT232 and it is not capable of powering the nrf24l0 as it can exceed 100ma on transmit, well beyond the capability of the chips. You’ll need an external 3.3 LDO regulator.

There are small NRF24 interface boards available on eBay for $1 (US) that provide the proper regulator and caps. The NRF24 plugs into a 8 pin female header on the board, Nano connnects to 8 pin male header on the same board. I use the boards for all my NRF24 projects, regardless of the Arduino type, it’s a clean solution.