external links in sidebar are not opening correctly

Hi,
I am trying to put some external links on the sidebar of my blog. But either I do it by putting the code into a text widget or directly into sidebar.php code, external links aren’t opening correctly.

i.e. I added a link say http://external.com in the sidebar. but when i try to open it, it ends up at a page http://mydomain.co/”http://external.com” and shows a 404 error.

plz help me out with this