KineticaRT:
I am using an Arduino Mega 2560 with only an Ethernet Shield. I want to power an external wireless and display device from the Mega's 5V supply.Can anyone tell me the maximum current taken by the Arduino Mega 2560 and the Arduino Ethernet Shield. I can't find this specified anywhere. I believe that the 5V regulator is capable of delivering 800mA.
Thanks
Well the answer depends on a lot of variables. USB power or external DC power through the external power connector?
USB power is limited by the 500ma polyfuse on the board. External power is limited by the on-board regulator's over current and over temperature automatic shutdown protection circuits. How much heat dissipation for the regulator is determined by the actual current being drawn and the voltage drop across the regulator (that is DC input voltage - 5.0 X current). So it's hard to give an exact figure and that is why there is no published Arduino spec for your question, too many variables not under total control of the arduino board.
Lefty