Power Supply for arduino + leds

Hi,

I want to build an Arduino on a breadboard like it is described on the Arduino website:

but i am not sure if my power supply is really OK for that?!

I bought one with a DC output of 9V at 1000mA, is that really OK (in the description they wrote 9V is suitable but what is the "real world" experience?)

And I also have a second question appending to this topic, because with this Arduino I want to power up some LEDs (max. 25 at the same time) do I have to use transistors between the Arduino / shift registers and the LEDs or is it OK to connect them directly also in long term usage?

I hope that someone has some experience on that ^^ and thanks so far for any answer :slight_smile:

Yes that power supply is fine.

How much current are the LEDs drawing. You have amongst other things a 200 mA limit per rail, so that means you can power less than 20 LEDs running at 20 mA but if you drop the current to say 15 mA each then you should be able to do it.
Look at the processors data sheet for how to distribute the led driving pins over the ports you have.