External Power Supply - 300mA enough?

I’m sorry if this question has been asked before, but the results of my search were poor.

This is regarding the duemilanove

I have an external dc adapter capable of outputting 1.5 - 9v and sourcing 300mA of current. Is this enough? Also, i understand that the recommended input voltage is between 7 - 12 volts. Am i better off with 7 as compared to 12 or vice versa?

Depends on what you want to connect to the board in the way of sensors or displays or outputs. Get an ammeter (a digital volt/ohm/amp multimeter) and measure the current at the plug. You wire the meter in series with one post of your power supply, so all the power you send to your board goes THROUGH the ammeter. I think someone said that with nothing plugged in, you can expect about 40mA?

As for 7~12VDC, anything goes in that range. The higher the voltage, the more energy is wasted by the voltage regulator as heat, but it doesn’t change the capability of the board to cope.

Thanks for the quick reponse halley.