A buck converter is a type of DC-DC converter that steps down voltage while maintaining high efficiency. It uses a switching element, typically a transistor, to control the flow of energy from a higher voltage source to a lower voltage output. This process involves storing energy in an inductor and releasing it at a lower voltage, making it ideal for applications where power efficiency is crucial. These converters are commonly used in various electronic devices, such as laptops, smartphones, and LED lighting, to provide the necessary voltage levels for different components. By efficiently converting power, buck converters help extend battery life and reduce heat generation in electronic systems.