How do you power arduino with a 9V battery?

Projects General Guidance
1

Can I use LM7805 voltage regulator with 9V battery to power arduino Uno board? Can someone point me to how I can connect it with frying up arduino board. 9V input into voltage regulator and 5V output from voltage regulator is the requirements. I need to use 9V because the little project I do require 9V, so someone let me know how I can do this? A simple circuit to connect it would be greatly appreciated.

Thanks

2

You simple wire the 9 volt battery to a power plug and insert it into the arduino's external power socket connector. There is already a 5vdc regulator on board to convert that voltage to what the board needs.

That being said, those small 9 vdc batteries are a very poor choice to power an arduino board because of their very high cost per mah capacity and their limited max current draw avalible. Building a battery pack from AA alkaline cells is a much better solution, or better yet a rechargeable battery pack of adequate capacity. And unless one really needs the portability of battery power an external wall wart DC power pack is better yet.

Lefty

3

Very simple, have a look at this -> http://www.bajdi.com/powering-arduino/battery-to-arduino/

4

@ Bajdi:

How do you connect the jack? What is the -ve and +ve terminal in the jack?

5

Case is ground and tip is positive lead.

2.1mm barrel plug, positive tip

6

Attached is the photo of the plug. Is the marking correct?

Untitle.png

7

Is the marking correct?

Exactly wrong.

8

Then, shud it be the other way around? :S

9

Then, shud it be the other way around?

There are normally only two different ways of wiring a plug like this; you described the wrong way.

10

@AWOL,

You are making it complicated. If what I marked is wrong, then the correct way should be the other way, isn't it?

11

It's a binary, right/wrong choice.
What's complicated?

12

yaantey:
You are making it complicated. If what I marked is wrong, then the correct way should be the other way, isn't it?

Yes, that's why his answer was not overly complicated, it was exactly correct. Incidentally, it's quite easy to see what part of the barrel is connected to which tag by using even a cheap'n'nasty multimeter.