I have a school-kit van De Graaf generator. I am fiddling around with
the charge loading brush.

Supplied with the kit there is what I have to call a "starwheel", like
a swastika with the bars at the ends shaped into points :-

_____________ | \ | _________ / | |

which fits on the top of the dome and rotates to show up the electron discharge from the points. At start-up the star-wheel surges one way, then the other, which I interpret as positive or negative voltage on the dome. To my surprise it turns best with the points LEADING. My question is this: Which shows positive potential and which shows negative? Points leading or points trailing?

Michael Bell

Supplied with the kit there is what I have to call a "starwheel", like

_____________ | \ | _________ / | |

*/\ | | | | | | | |_____________ |_____________ | 0 | |_ ______________ __________ | | | | | | | | | | | | | ______| | \/*/ | \__________|which fits on the top of the dome and rotates to show up the electron discharge from the points. At start-up the star-wheel surges one way, then the other, which I interpret as positive or negative voltage on the dome. To my surprise it turns best with the points LEADING. My question is this: Which shows positive potential and which shows negative? Points leading or points trailing?

Michael Bell