This is the first non-linear electronics class that introduces the students to the fundamentals of the circuit design through the architecture of a modern electronics system at the interface with sensors and actuators. Modeling of the non-linear devices, diode and MOS transistors, is presented, along with basic properties of MOS transistors for analog (amplification) and digital (switching) IC circuit design. Operational amplifier ideal and non-ideal models are explored along with the concepts of the feedback and stability. Signal conditioning circuits (fixed-gain, difference and instrumentation amplifiers, active filters), signal shaping circuits (rectifier, clipper, peak detector) and oscillators are presented. Basics of sample and hold circuit, data converters, digital signal processing platforms and radios are presented.