On-off control is a simple method used in various systems to maintain a desired state, such as temperature or pressure. In this approach, a device, like a thermostat, turns a system on when a certain threshold is reached and turns it off when that threshold is crossed. This creates a binary operation, where the system is either fully operational or completely inactive. This type of control is commonly found in household appliances, such as heaters and air conditioners. While on-off control is easy to implement and cost-effective, it can lead to fluctuations in the controlled variable, resulting in less precise regulation compared to more advanced control methods.