What device is used to automatically adjust the primary voltage of a line to ensure optimal voltage range?

The device that is used to automatically adjust the primary voltage of a line to ensure it remains within an optimal voltage range is the regulator. Voltage regulators play a crucial role in electrical systems by maintaining the voltage level within designated limits, compensating for fluctuations and ensuring that the service remains stable. They automatically modulate the voltage to counteract any changes caused by load variations or other factors.

In operation, these regulators adjust the voltage in real time, which helps to protect sensitive equipment and maintain system efficiency. This functionality is particularly important in maintaining the health and operation of both the electrical grid and the devices connected to it. The ability to adapt to changes without requiring manual intervention is a key characteristic of voltage regulators, distinguishing them from other devices that may be involved in the broader electrical distribution system.