In a basic electric control system, an example of a controlled device is a:

In a basic electric control system, the controlled device is essential for regulating or controlling certain conditions within a system, such as temperature, pressure, or humidity.

The fuel valve serves as a controlled device as it directly manages the flow of fuel to a heating appliance or furnace based on signals from the control system; this ensures that the system operates safely and efficiently. When the control system detects a need for heating, it activates the fuel valve to allow fuel to flow, ensuring that the appliance can generate heat as required.

In contrast, devices like pressure-stats, humidistats, and thermostats primarily serve as sensors or controllers that monitor specific environmental conditions. While they play a crucial role in the overall control system by providing feedback to the control device (like opening or closing a circuit to the controlled device), they do not directly control a physical element in the way that a fuel valve does. The fuel valve is the component that directly interfaces with and regulates fuel delivery, thereby qualifying it as the controlled device in this context.