A hydraulic pilot-operated DCV typically uses which to actuate the main valve?

• A. A mechanical handle
• B. A solenoid coil
• C. A pilot signal from a separate source
• D. An electric motor

Answer: (C)

In a hydraulic pilot-operated valve, the main spool is moved not by a direct electric or manual push, but by hydraulic pressure generated in a pilot stage. A small pilot valve creates a hydraulic signal in a pilot chamber, and this pressure shifts the main valve to open or close the flow as controlled. The key idea is that control signals come from a separate source and are converted into a hydraulic pressure that actuates the main valve. This setup lets you control large flows with a small, efficient control signal, often remotely, while keeping the main actuation hydraulic rather than direct electrical or manual movement.