5V-PIN of Arduino mega 2560 R3 suitable for driving this ?

Official Hardware Mega Mega 2560
1

hi,
Arduino mega 2560 R3 has a 5V pin.

May this be used to supply the Arduino or is it only for output ?

in my project the arduino drives an lcd-modul via I2C, lcd is driven by 5V,
other pins will use same level for input or output.

2

If the Arduino board has a power supply correctly connected to either the USB Jack or the DC power jack, then the 5V pin provides access to the Arduino 5V system voltage. The LCD display might be powered with 5V by connecting to the Arduino 5V pin assuming that it does not require more current than is available. Without knowing the exact LCD display specifications for your device, I can’t say for certain.

If you provide more information about your hardware, intended wiring schematic, and Arduino power source, then this forum can provide you with better answers.

3

The 5V pin can power a small number of devices, or low power.

The 5V pin should not be used to power the Mega2560 itself - if you feed in 5volts here then you are also "back-feeding" the onboard 5volt regulator which will be wasting some power and bypassing onboard protections.

The best way to power the Mega2560 is with 7V to 12V in the barrel jack. I use about 8 or 9 volts. There is also a Vin pin which works but this bypasses a protection diode.

4

thank you very much for answers !
dont know what is meant with barrel..i'm german lang.
there is a Vin pin near the 5V-Pin, which i used for input of 7-8V like
said here..the lcd is hd44780 (1602A) used in 2line output over I2C,
so i guess the 5V-Pin can be used to supply it as you wrote ?

5

Hi @lupus51.

This is the barrel jack on the board:

image
image261×306 43.6 KB

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A000067_00.front_643x483.jpg by Arduino - CC BY-SA 4.0 (cropped, annotated, border added)
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6

thanks for the picture..ok so far

meanwhile i have adjausted a step-down-converter to 8V, which is now connected with Vin-Pin.
I guessed, that at the 5V-Pin will appear 5V .. but i am surprised :slight_smile: voltmeter shows 8V here too !?????
and the other pins (reset,3V3) show 8V too !???

guess, the A.mega is damaged..

7

How have you connected the meter?

8

Minus to GND in the same pins-line, Plus to the PINS for 3.3 or 5V

the backside at this does Not show logical tho naming, the above listed pins seem
to be connected...

did i get a fake-version ?
had got it from aliexpress.com

9

ok, there's nothing damaged and nothing of fake..
only a broken wire at GND-connections between A.mega and Voltage regulator
made the show..
now all works fine :grinning_face:

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