Proportional control valves are always controlled with an electronic voltage or current signal.

• A. True
• B. False
• C. Not applicable
• D. Both

Answer: (B)

Proportional control valves adjust their opening in direct proportion to the command input. While electronic voltage or current signals are the common way to drive many of these valves, not every system uses that form of input. Some designs rely on a pilot pressure or a manual adjustment to set the position, and others are part of a larger control chain where the final position is achieved through a combination of signals and pressure sources. Because the input form can vary by design, the statement that they are always controlled with an electronic voltage or current signal is not accurate.