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 rapidly turn on and off, controlling the amount of energy transferred to the output. This process allows it to reduce the input voltage to a lower output voltage, making it useful in various electronic applications. These converters are commonly found in power supplies, battery chargers, and portable devices where efficient power management is essential. By minimizing energy loss, buck converters help extend battery life and improve overall system performance.