File talk:Van de Graaff generator.svg

Positive charge, where from

I think, the german version (Van-de-Graaff-Generator) is better understandable, as it is. I don't know exactly where the positive charge come form at your version. I think that at (7) it could be not on ground, but positive potential. What do you think about this version? -- Arpad Horvath 14:54, 30 June 2006 (UTC)

Corrections

I have corrected this figure to reflect the real process, as I explain to my students using a real one. It was wrong to have charges of only one sign in each side. What happens is that because of friction the plastic cylinder acquires some charge (negative in this case) and the belt the opposite (positive) that ascends. Now, when this positive charge reaches the top attracts electrons (leaving the shell positively charged). When the belt descends is neutral. Then at the bottom the negative charge of the plastic cylinder repels the electrons that go to ground.
Which "plastic cylinder" - the description says plastic on the top - metal at the bottom? (I remember it reversely, but it was 50 years ago).--J. K. H. Friedgé (talk) 10:28, 31 January 2013 (UTC)