Basic effects of electrosurgery

Desiccation: Direct contact of the instrument and the tissue causes dehydration and protein denaturation. Continued application of heat with no or minimal tissue penetration results in superficial carbonization (char).
Vaporization: No direct contact, electrode is held at the tissue surface; the high heat generated by the current vaporizes tissue. Since the cells "explode," no char is produced.
Fulguration: No direct contact, electrode is held a bit further away than in vaporization; electrical current (sparks) arcs between the electrode tip and the nearby tissue, which causes it to char.