Re: Positive vs Negative Van de Graaff Polarity
- --- In VanDeGraaffGenerator@yahoogroups.com, "juke_family" <juke_family@...> wrote:
>Long sparks only occur if the ionization of the air starts at the positive end of the spark. With a negative terminal the breakdown occurs at your hand when you move it close enough from the terminal and the resulting spark is long and powerful.
> I made an attempt to reverse the polarity of my small Science First generator. I put Al foil on the bottom Teflon roller and Teflon tape over the top Al roller. It seemed to work, but I noticed that the sparks were less frequent and more painful in the negative mode. Is this typical?
With a positive terminal you get only corona before the distance is of only a few cm.
Long sparks are less frequent because it takes more time to accumulate enough charge and voltage.
Antonio Carlos M. de Queiroz