Semiconductor Devices: Diodes and Transistors (BJT, MOSFET)

Semiconductor devices form the fundamental building blocks of modern electrical engineering, particularly in the realm of power electronics. These tiny components, crafted from materials like silicon or germanium, possess unique electrical properties that allow us to control and shape the flow of current with remarkable precision. Understanding their behavior is essential for designing efficient and reliable power systems, from simple adapters to complex grid-scale converters.

The diode is perhaps the simplest yet most crucial semiconductor device. Essentially, it acts as a one-way valve for electrical current, allowing it to flow freely in one direction (forward bias) while blocking it almost entirely in the opposite direction (reverse bias). This directional property stems from the PN junction formed by joining P-type and N-type semiconductor materials, creating a depletion region that dictates current flow.