Electrosurgical system with a radio frequency amplifier

An electrosurgical instrument comprising: a first jaw (102) having an upper and lower surface, a first electrode (103a), a second electrode (103b), a third electrode (105a) and a fourth electrode (105b); and a second jaw (104) having an upper and lower surface and a fifth electrode (107), wherein the third electrode (105a) is disposed on the upper surface of the first jaw facing the fifth electrode (107), the first and second jaws are pivotally coupled together and configured to deliver radio frequency (RF) energy to the tissue between the third and fifth electrodes, the fourth electrode (105b) being placed in the middle of the first jaw and disposed on the lower surface of the first jaw, characterized in that the fourth electrode (105b) has an elongated part that extends longitudinally following along a part elongated portion of the first jaw and extending at a distal portion curving upwards along a tip of the first jaw, configured as the first electrode, the second electrode and the fourth electrodes to transmit RF energy between them to cut tissue outside, below and in front of the tip of the second jaw and in contact with the first, second and fourth electrodes.