PN Junction Theory

A PN junction is a fundamental component in electronics formed by joining two types of semiconductor materials: p-type (positive) and n-type (negative). The p-type has more "holes" (positive charge carriers), while the n-type has extra electrons (negative charge carriers). When they meet, electrons from the n-type fill holes in the p-type, creating a depletion zone that acts as a barrier. This allows current to flow easily in one direction (forward bias) but blocks it in the opposite direction (reverse bias). This property is crucial for devices like diodes and transistors, enabling control of electrical signals.