This course covers the operating principles, analysis and applications of semiconductor devices underpinning electronic systems. It builds on the foundational electrical concepts developed at level I and provides an in-depth exploration of important non-linear devices: diodes, bipolar junction transistors and field-effect transistors. Equivalent circuit models for these devices are developed and applied to the analysis and design of practical systems, such as voltage rectifiers and amplifiers. Important system concepts are introduced along the way, including amplifier types, gains and frequency responses. The discussion includes op-amp circuits and non-idealities in practical devices, extending to active filter and resonant circuits. The course includes a practical component which develop key technical skills such as soldering and operating test and measurement instruments.