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Topic: Regulator Overheating with Ethernet Module Installed (Read 1 time) previous topic - next topic


I have a Mega 2560 that is running off of a regulated 12V power supply into the VIN and GND terminals (have also tried powering with a barrel connector).

When I run with just the Arduino connected everything works fine and the regulator gets warm (as expected) but definitely not hot.  As soon as I connect the Ethernet Shield and power up the Arduino the regulator gets so hot that you cannot touch it within about 30 seconds... Eventually shutting down the Arduino. 

Can anyone shed some light on whether this is a problem that can be fixed and where to look for the solution or do I simply have a bad Shield?

I also tried the Ethernet Shield on an Arduino Uno with the same results.  I understand that when running 12V (actually 11.85VDC) through the regulator the extra needs to be dissipated, however, I would not expect that the Ethernet Module should draw that much.

I should mention that when connected up to the USB port of my computer everything functions properly (can connect to internet) and it runs cool.

Thanks in advance.


You ideally want a 7.5V - 9V power supply to feed an ethernet shield, its a greedy begger.  (about 150 mA at 5 volts), Given the not so wonderful heatsinks on the arduino it gets hot......


Thanks for the response.

Just for fun I took a switching power supply off of an old router (2A @ 5VDC) and wired it up to a USB adapter.  It powered up the arduino fine but when I connected the Ethernet Shield the power supply started hissing.  I think that there may be a problem with the module after all.  It should not pull more than 2 Amps.  Funny that it worked from my computers USB port.  Glad it did not blow my USB.

Any other suggestions on things I can try before replacing it (it appears that everyone is backordered at the moment).


Funny that it worked from my computers USB port.  Glad it did not blow my USB.

The USB power is somewhat protected from over current draw by a on board 500ma polyfuse (thermo type) that automatically resets when the overcurrent condition is removed.



This is an old post , but i cant; find any help..
i have the exact same problem.

arduino mega works fine with 12v but when i hook up the ethernet shield gets hot.
i tried 2 different arduino mega and 2 different Ethernet shields.. ,
do i have to run with 9v?


Apr 07, 2013, 04:31 am Last Edit: Apr 07, 2013, 04:50 am by gc9n Reason: 1
there is an erratic behavior,when everheting, if i ping the arduino , the ethernet behaves like there is not present or resseting it self , but the arduino mega works fine.


I have the same problem here. Happy now that I am not alone ... lol.

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