Van De Graaff Generator
This is one of the most wonderful inventions man has ever made; its
sheer simple operation fascinate the physicist and the laymen alike. Its uses,
despite being a simple machine, speak volumes:
Nowadays, particle accelerators in nuclear laboratories use them
extensively to get the high voltages they need.
The blue pointer at the bottom, that is connected to
a very high positive voltage, generate positive ions. They in turn are deposited
on the moving belt. The belt carries them around the interior of the green dome
that results in the induction of negative charges inside the dome and a similar
positive charge outside.
The induced negative charges move along the brown rod
and neutralize some of the positive charges on the belt. That makes it possible
for belt to carry more and more positive charges, as it moves on, towards the
top. However, the induced positive charge outside the dome is increasing rapidly
and so is its potential, which can reach in excess of 107 Volts. This
potential is widely used for commercial purposes.