Which device controls pressure in a pneumatic system?

• A. Solenoid Valve
• B. Caliper
• C. OSHA
• D. Regulator

Answer: (D)

Pressure regulation in a pneumatic system is about keeping downstream air pressure stable for reliable operation of valves and actuators. The device that does this is the regulator, which automatically adjusts airflow to maintain a chosen output pressure. It senses the pressure at the output and uses a spring and diaphragm (or piston) to open or close a valve; when the downstream pressure is higher than the set point, it reduces flow, and when it drops, it allows more flow, keeping the pressure steady despite changes in supply or load. This keeps tools and cylinders predictable and protects components from overpressure. A solenoid valve controls the direction or duty cycle of airflow but doesn't set a constant pressure. A caliper measures dimensions, not pressure. OSHA is a safety agency, not a device. So the regulator is the component that controls pressure.