What is a characteristic of an on/off control method?

The characteristic of an on/off control method is that it switches states between on and off. This type of control is fundamental in many automation systems, where the control action is simply to turn a device on or off based on the feedback it receives.

In practical applications, this method is often used in systems like heating or cooling units, where the system only needs to know whether to operate (on) or not (off) based on certain setpoints or conditions. The simplicity of this method makes it easy to implement and effective for many control scenarios.

The other options describe characteristics that do not align with the nature of on/off control. Continuous output, for instance, would typically refer to modulation methods, which allow for a range of outputs rather than a binary state. Similarly, analog systems often involve a continuous spectrum of signals, while variable frequency control is associated with techniques such as variable frequency drives that allow for more nuanced control rather than simple on/off operation.