Linear regulation is a method used to maintain a constant output voltage from a power supply, regardless of changes in input voltage or load conditions. It works by using a variable resistor, or transistor, to adjust the amount of voltage dropped across it, ensuring that the output remains stable. This technique is commonly found in power supplies for electronic devices, as it provides a simple and effective way to regulate voltage. However, linear regulators can be less efficient than other methods, such as switching regulation, especially when there is a large difference between input and output voltages.