This document discusses regenerative braking systems. It begins by explaining conventional braking systems, noting that they waste up to 30% of a car's generated power as heat. It then describes how regenerative braking systems work, funneling the energy created during braking back into the battery. The key components are identified as the brake drum, friction lining, controller, electric generator, and linking mechanism. Diagrams are provided to illustrate how the energy is transferred back to the battery during braking. Advantages include reduced pollution and increased engine life by reducing energy waste, while disadvantages include added weight and costs. Regenerative braking has applications in electric vehicles and transportation systems to recover kinetic energy lost during deceleration.