I have never taken one personally. But a few of my aquantances have.. So I was wondering how exactly do they give one?
I have heard that they base it on blood presure and heart rate?
what happens if you go into one so mad that both are already sky high? It can't go up much farther!
I just would like to know how they actually give one and how they make a judgement one way or another?
Blood pressure and heart rate are indeed important indicia in the scoring of polygraph charts. You'll find a detailed description of how polygraph "tests" are administered and scored in Chapter 3 of The Lie Behind the Lie Detector (http://antipolygraph.org/pubs.shtml). (I recommend you download the PDF version; it's more detailed than the currently available HTML version.)