A low-dropout regulator (LDO) is a type of voltage regulator that maintains a steady output voltage even when the input voltage is only slightly higher than the desired output. This feature allows LDOs to operate efficiently in battery-powered devices, where maximizing battery life is crucial. They are commonly used in applications like smartphones, tablets, and microcontrollers. LDOs are characterized by their low dropout voltage, which is the minimum difference needed between the input and output voltages for proper regulation. This makes them ideal for situations where space is limited and power efficiency is essential. They are simple to use and require fewer external components compared to other types of regulators, such as switching regulators.