user77621: I have an AA battery holder for 9V. Two wires come out of it, one for positive and another for negative. How can I wire it up to my Arduino Uno? It kind of looks like this.

user77175: I would suggest a barrel jack, you know, ones on eBay. For instance, those 2.1 x 5.5mm barrel jack connectors. Just solder the positive and negative wires respectively with barrel jack. Here is a link: eBay Barrel Jack
Make sure the red or the positive goes with the red on the Barrel Jack and that the black or negative goes with the black of the Barrel Jack. Like in the image.

77621: <p>I have an AA battery holder for 9V. Two wires come out of it, one for positive and another for negative. How can I wire it up to my Arduino Uno? It kind of looks like this.<a href="https://i.stack.imgur.com/yY7ga.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yY7ga.jpg" alt="" /></a></p>
 77175: <p>I would suggest a barrel jack, you know, ones on eBay. For instance, those 2.1 x 5.5mm barrel jack connectors. Just solder the positive and negative wires respectively with barrel jack. Here is a link: <a href="https://www.ebay.com/itm/253803093868?_trkparms=ispr%3D1&amp;hash=item3b17d7df6c:g:pYMAAOSwGHxcz6-n&amp;amdata=enc%3AAQAGAAACkPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSg3Ye8yTWgOW7pmE1t838dpT7AD8sxbO0VOebe4CPmrZXmmDuPDQbE9XxV%252FUmz3za4AS5ntxim9hOFB2pETiXAThNaYYqnoMlalCssp2ACiM7XXERF9akKV%252F6Tq2qJdFDgLxur%252Fv4t%252Ba2pGI%252FHzRP3shGkNm2lN3jrtycgpR94QtVVMJ%252FHu1oKp8m3LtYYIzEqHmQjISkX%252BFgJ0exzhcoXEha0jgcKAiXNUfUQM0cIZBuihJCKqEQCvTvzCrjt2wQa7tlmU4AGgzYCq95nTn%252FS10%252Bf3hAqkeCqpd6TGCagQOkLqjRBHER6iU6mJAaKEqXUEtN4b3iEiVz9OfmhlpfPB%252F52U2rAxQliOYKxIPh9S8hZJtnKbLt%252FiuGHcCG%252B%252Fx3pgY9uZs6zVqsRoz%252BIhI0l9nqU2HpOuXUZ2HLcnwxoO%252FCuHq%252FeqGcIL3uSQ4D7PpAXEdBafbEDWeTMGTNWNDbTKVUtgueh4hjHHl2Lpcku879o2oC5wwIi%252FftrAGgdKHl5Yk9wK%252FqYU2eCbEAIZKKctbUln%252BE2GDw2ogZYLEuCTzoX1QLTY9LRWO04jLjv00wfzPjjiwwAXflc94l0TBQfLwL69V1kyAUJIzdu8YUC2QnCxGH1SAxG2mP6XIQk4aMYKQKgABjWJ0OCMEzQVt%252FQd7eTvMa7sDHt%252BKDKWeut9r6ZlVwkYGzOSONjk%252FAwalDqo2m4saH2cXBV4rRSQ%252FSpyLlzPeL11fvw72KSWqPFJOofdpmBz6uquwAuO0Sshh8YZgKSIuG9S17tD83X7exn80usxYzywvpuIWwCwdN8%252FfzY%252FvYwDEvRwQyy2iuIFLF%7Ccksum%3A2538030938687aaa9e7bf0fe4519aef2c1b3df89dd93%7Campid%3APL_CLK%7Cclp%3A2334524" rel="nofollow noreferrer">eBay Barrel Jack</a>
Make sure the red or the positive goes with the red on the Barrel Jack and that the black or negative goes with the black of the Barrel Jack. Like in the image.<a href="https://i.stack.imgur.com/i764b.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/i764b.jpg" alt="This is what I mean by soldering the wires to the barrel jack." /></a></p>
