A generator for generating high voltage pulse waveforms for tissue ablation, comprising: a set of electrode channels (1401, 1402, 1403) coupled to a set of electrodes during use, each electrode channel from the set of electrode channels including a first switch (1420, 1420', 1420") from a first set of switches and a second switch (1430, 1430', 1430") from a second set of switches; a set of energy sources (1460, 1460', 1460") coupled to a third set of switches (1462, 1462', 1462"), the third set of switches configured to switch from an OFF state to an ON state to couple the set of energy sources to the set of electrodes; a set of resistors (1470, 1470', 1470") coupled to the second set of switches, the second set of switches configured to switch from an OFF state to an ON state to couple the set of resistors to the set of electrodes; a sensing circuit configured to measure an output current of the set of electrode channels; and a processor coupled to the first set of switches, the second set of switches, and the third set of switches, the processor configured to: set a subset of the third set of switches to the ON state to couple a subset of the energy sources to the electrode channels; set a subset of the first set of switches to the ON state and a subset of the second set of switches to the ON state to configure a first subset of the electrode channels as anodes and a second subset of the electrode channels as cathodes; deliver a first pulse waveform to the first subset and the second subset of electrode channels using the subset of energy sources, such that the output current is measured by the sensing circuit; and in response to the output current measured by the sensing circuit being different from a predetermined output current, adjust at least one of a voltage delivered by the set of energy sources or a resistance value of the set of resistors such that a second pulse waveform delivered after the adjusting has an amplitude different than the first pulse waveform. a set of electrode channels (1401, 1402, 1403) coupled to a set of electrodes during use, each electrode channel from the set of electrode channels including a first switch (1420, 1420', 1420") from a first set of switches and a second switch (1430, 1430', 1430") from a second set of switches; a set of energy sources (1460, 1460', 1460") coupled to a third set of switches (1462, 1462', 1462"), the third set of switches configured to switch from an OFF state to an ON state to couple the set of energy sources to the set of electrodes; a set of resistors (1470, 1470', 1470") coupled to the second set of switches, the second set of switches configured to switch from an OFF state to an ON state to couple the set of resistors to the set of electrodes; a sensing circuit configured to measure an output current of the set of electrode channels; and a processor coupled to the first set of switches, the second set of switches, and the third set of switches, the processor configured to: set a subset of the third set of switches to the ON state to couple a subset of the energy sources to the electrode channels; set a subset of the first set of switches to the ON state and a subset of the second set of switches to the ON state to configure a first subset of the electrode channels as anodes and a second subset of the electrode channels as cathodes; deliver a first pulse waveform to the first subset and the second subset of electrode channels using the subset of energy sources, such that the output current is measured by the sensing circuit; and in response to the output current measured by the sensing circuit being different from a predetermined output current, adjust at least one of a voltage delivered by the set of energy sources or a resistance value of the set of resistors such that a second pulse waveform delivered after the adjusting has an amplitude different than the first pulse waveform. set a subset of the third set of switches to the ON state to couple a subset of the energy sources to the electrode channels; set a subset of the first set of switches to the ON state and a subset of the second set of switches to the ON state to configure a first subset of the electrode channels as anodes and a second subset of the electrode channels as cathodes; deliver a first pulse waveform to the first subset and the second subset of electrode channels using the subset of energy sources, such that the output current is measured by the sensing circuit; and in response to the output current measured by the sensing circuit being different from a predetermined output current, adjust at least one of a voltage delivered by the set of energy sources or a resistance value of the set of resistors such that a second pulse waveform delivered after the adjusting has an amplitude different than the first pulse waveform.