Which automatically turns off a compressor when air is no longer needed?

• A. Regulator
• B. Filter
• C. Muffler
• D. Pressure Switch

Answer: (D)

The system uses a pressure switch to manage the compressor. This switch watches the air pressure in the tank and automatically starts the compressor when pressure falls below a set point and stops it when pressure reaches a higher set point. That on-off control keeps the system within safe limits and avoids running the compressor wastefully when air isn’t needed.

Other components have different roles. A regulator lowers the pressure for use by tools but doesn’t decide when the compressor runs. A filter removes contaminants, and a muffler reduces exhaust noise. Neither of these controls the compressor’s on/off cycling.