Talk:Cathode

hi, just clearing up some basic concepts

anodes and cathodes are defined by their relationship between the source of the electrical energy, and the thing which receives that electrical energy. on the source of the electrical energy, the anode negative, while the cathode is positive,and on the thing which receives electrical energy the polarities are opposite. hence a discharging cell has a negative terminal anode but a cell being recharged or undergoing electrolysis has a positive terminal anode instead is this correct?

The part of the cathode ray tube is incorrect. The electrons flow off of the negnative terminal: http://electronics.howstuffworks.com/tv3.htm —Preceding unsigned comment added by 75.187.47.144 (talk) 01:11, 18 May 2008 (UTC)[reply]

Ok. As far as I can tell the Cathode-ray tube is a historical mishap, but I can't tell why. The Hall Effect (1879) unambiguously determined that electrons were the carriers of current, and the cathode ray tube was invented in 1897 (Thompson), so it's not clear to me why they would call the terminal where the electrons are coming out as the "cathode".

But, either way, the definition on this page (cathode = positive (conventional) current out (neg in), anode = positive in (neg out)) works for everything except for CRTs. Circuit diagrams (physics), electronics, galvonic cells (chemistry), electrolytic cells (chemistry), all seem to be fine with this definition. As for the CRTs, it would be nice if a historian could help fill us in on this, but you'll just have to chalk this up to a historical accident, because every page (including the wikipedia page on cahode rays/CRTs) say that the cathode is where the electrons current comes out.