Our lecture describes a current-based MOSFET model, which consists of simple, continuous, and accurate single-piece expressions, valid for all regions of operation. This model preserves fundamental properties, such as charge conservation and the source-drain symmetry of the MOSFET. Only a small set of parameters is required to describe our MOSFET model. The accuracy and scalability of the model are certified by the measurements of the transconductance- to-current ratio for different technologies, dimensions and gate voltages. The design of a common-source amplifier illustrates the application of the current-based MOSFET model.