The function of the electrosurgery unit is to produce a cutting effect which does not require physical pressure (as required when using, for example, a scalpel). The technical objective is to cause the tissue cells to "explode" through the intense heating of the cell's watery contents, which expand as the water turns to steam. The cell wall is therefore ruptured and the cutting effect obtained.

The intense heating of localised cells is achieved using two phenomena:

1. Body cells resist the electrosurgery current being passed through them with the result that the contents of the cell are heated.
2. The high energy "spark" from the electrode itself, where energy is released as heat.

The two phenomena are harmonised in electrosurgical cutting which is a complex interaction between the properties of radio frequency (R.F.) and the body itself. This is simplified in the following explanation.

The objective is to rapidly heat the cell contents to effect explosion and convert the watery contents to steam, thereby leaving a gap in a group of cells and hence forming the incision in the tissue. This heating effect is only local, as the heat is dissipated in the steam and is therefore not transferred to adjacent cells. As the electrode is moved through the tissue, new cells are brought into contact with the current and are likewise exploded to form the incision.

The cells left as a result are relatively nonconductive (being desiccated and dry) and will not readily pass more current to obtain the heating effect through electrical resistance. In this manner with cutting, effect is precise and controllable with the advantage that the incision is dry and hence comparatively bloodless.