Unregulated power supply

Hi

I am connecting 6 buttons and 6 20mA LEds to An arduino, mains powered, and need to find the right power lead to use.

This one here says unregulated
http://www.maplin.co.uk/Module.aspx?ModuleNo=46107

"Regulated means that the output will be as advised (such as 12v) no matter what the input. Unregulated means that although the output is advised (such as 12v), the input voltage determins whether this would be correct (ie, if the input voltage is higher the supposed, the output will be higher than advised)"

Whats the worst that would happen to the Arduino if I use unregulated power supply? Should I try and find a regulated power supply?

THanks

The DC power jack on an arduino feeds the regulator, so an unregulated supply is fine. The output must be more than ~7.6V (regulator overhead + protection diode dropout), and the larger it is the more the regulator will heat up. A nominal 12V or 9V unregulated supply should do just fine.

I use a 12V unregulated supply (old amplified computer speaker wall-wart) to power some of my arduinos.

-j

Be careful that your LEDs and other add-ons to the board don't exceed 150ma. 6x20ma should be fine, but it gets you close. I had this problem just a few days ago.

-Chase

Be careful that your LEDs and other add-ons to the board don't exceed 150ma. 6x20ma should be fine, but it gets you close. I had this problem just a few days ago.

This would only be an issue for the ATmega power, not the arduino's regulator and any peripherals that are not powered directly from an ATmega IO pin.

You can get 500mA (or more, depends on the arduino model) from a standard arduino's regulator.

-j