As demand on the device shown in the illustration fluctuates in the pressure range of 100 to 110 psi, the output of the unit is controlled by __________. GS-0119

Correct Answer: Option B — the modulation of the opening of a butterfly valve located in the air intake

Modulating the air intake butterfly valve is a standard method for controlling compressor capacity. By restricting the intake air, the compressor handles less mass flow, effectively matching output to demand without requiring frequent motor starts or stops, which protects the electrical system and mechanical components from excessive cycling.