How is suspense and tension created in both stories Tell Tale Heart and Black Cat ?

I'm not sure about the Black Cat, but we've been doing the tell-tale heart at school. The fact that we don't know any details about the setting, the narrator or the victim builds tension because it makes it seem closer to home.

The narrator seems to be mad, because he kills this guy for no reason. This builds tension because the reader doesn't know what's going to happen next; they can't comprehend his (or her) mindset.

The repitition, capital letters and exclamation marks add shocks and make the reader jumpy.

The whole thing about the eye, and the fact that everything happens at midnight etc. builds suspense because modern kids are taught to fear 'the witching hour', ie. midnight, and 'the evil eye', from the time when they first start to hear fairy stories. Poe uses this to make the reader feel apprehensive.