Designed, modeled, and analyzed a DC-DC buck converter to step down input voltage while maintaining stable and efficient output under varying load conditions. Derived steady-state relationships between duty cycle, input voltage, and output voltage, and evaluated key performance metrics including output voltage regulation, inductor current ripple, and conversion efficiency. Selected appropriate component values (inductor, capacitor, and switching frequency) based on design constraints to ensure continuous conduction mode operation and minimize ripple. Simulated circuit behavior and validated analytical results through waveform analysis, examining transient response, switching losses, and efficiency trade-offs. Explored the impact of load variation and non-ideal components on system performance to understand practical design limitations.