Graphical abstractDisplay Omitted We model the effects of an oxide breakdown on the transistor behaviour.We consider the potentiometer model.We show how the relevant feature that characterize the dielectric breakdown affect the transistor's transconductances. In this work, the effects of a gate-to-channel dielectric breakdown on the output characteristics of advanced La2O3-based metal-oxide-semiconductor field-effect transistors (MOSFETs) are investigated. The electrical behaviour is modeled using a potentiometer-like resistor network. It is shown how the relevant features that characterize a breakdown event in an MOS transistor: location of the failure site along the device channel, post-breakdown oxide resistance, and post-breakdown channel resistance, affect the mutual and drain transconductances of the device. The connection with the nonlinear current source model for broken down transistors is also discussed.