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Topic: Using USB Poweradapter 5.2V/1000mA for Yun ? (Read 1 time) previous topic - next topic

_Alain_

Hi

They say that the adapter above is made especially for the raspberry pi and as far as I know the raspi is made for 5V as well (why is the the adapter 5.2V then ?).
Can I use the above Poweradapter for the Yun as well ?

Kind regards
Alain

ShapeShifter

#1
Feb 05, 2016, 01:25 pm Last Edit: Feb 05, 2016, 01:26 pm by ShapeShifter
Do you have a link to the adapter? I'm guessing it's from Adafruit? They have adapters that put out a bit more than 5V to compensate for the voltage drop in the wires and connectors so that a full 5V actually reaches the board.

No power supply is exactly the stated voltage, there is always some variation of some magnitude. A standard voltage tolerance is +/- 10%, meaning that a 5V input should be happy with 4.5 to 5.5 Volts. The 5.2V supply is well within that range.

In the case of the Yun, the extra 0.2 Volts may be particularly helpful: the power coming in through the USB connector first passes through a diode, which causes a slight voltage drop, meaning that the internal circuitry sees something less than a true 5V. This is believed to be the cause of some issues with USB devices that are plugged into the Linux host USB port, and the extra supply voltage should help counter that.

Personally, I wouldn't be afraid of using that adapter with my Yun (in fact, I already have used the Adafruit 5.2V adapter with a Yun) but I can't be responsible for any issues you may have if you do so.

sonnyyu

#2
Feb 05, 2016, 05:02 pm Last Edit: Feb 05, 2016, 05:04 pm by sonnyyu
...
In the case of the Yun, the extra 0.2 Volts may be particularly helpful: the power coming in through the USB connector first passes through a diode, which causes a slight voltage drop, meaning that the internal circuitry sees something less than a true 5V. This is believed to be the cause of some issues with USB devices that are plugged into the Linux host USB port, and the extra supply voltage should help counter that.
...
Arduino Yun release 5 from arduino.org ( all the board shipped since last summer) is fixed 5v pin/USB port problem!

Arduino Yun 5v pin/USB port doesnt provide 5 volt.

http://forum.arduino.cc/index.php?topic=209836.msg1542386#msg1542386

4.48 volt at 5v pin will cause some shield fail, and low voltage at USB port cause a lot of USB device fail.

Arduino Yun release 5 is fixed 5v pin/USB port problem, provide exactly 5 volt which I saw the demo at maker faire nyc yesterday.




sonnyyu

#3
Feb 05, 2016, 05:12 pm Last Edit: Feb 05, 2016, 05:13 pm by sonnyyu
Do you have a link to the adapter? I'm guessing it's from Adafruit? They have adapters that put out a bit more than 5V to compensate for the voltage drop in the wires and connectors so that a full 5V actually reaches the board.
...
Power voltage instability with temperature.

http://forum.arduino.cc/index.php?topic=190300.0







my 2 cents:
1. Voltage instability with temperature.
2. AR9331 no effect by Voltage instability since it power by 3.3 V.
3. Shield is power by 5.0 V which has 2 diodes and lowest  voltage.

4.48 volt  is normal but might cause some shield fail.


_Alain_

OK, thank you guys for the explanations.
Long story, short answer is: Yes. Right ?

Kind regards
Alain

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