Principle of lightining conductor

[logearav]

friends,
in lightining conductor, a metal plate with number of spikes is connected to the top end of the conductor and kept at the top of the building.
when a negatively charged cloud passes over the building , positive charge is induced on the pointed conductor. the positive charge ionise the air in the vicinity.
What happens next? how the negative charge of the cloud is neutralized
thanks in advance

 

[tiny-tim]

Hi logearav!

A lightning conductor attracts lightning …

the idea is to get the lightning to go through the conductor, safely to earth, instead of into the building!

For details, see http://en.wikipedia.org/wiki/Lightning_rod