kdun0001:
i'have a problem with ardunio. the problem is that when i'm connected with the pc it's working however when connecting it with the 9v battery not all components are functioning. what should i do its is possible to conenct another battery of 9V??
You need to be more specific. What else do you have connected to the Arduino? What components are not functioning?
As has been mentioned, 9V alkaline batteries cannot provide much current - they can power an Arduino and a few LEDs or an LCD display and backlight, but not much more. The Lithium variants are a lot better (see http://data.energizer.com/PDFs/la522.pdf) but expensive. A stack of 4 or 6 AA cells is much better value if you have the space.