Current sink modules are characterized by which statement?

• A. Current flows into the field device
• B. Current flows out of the field device
• C. Current circulates freely in the circuit
• D. No current flows through sink modules

Answer: (B)

Current sink modules pull current from the field devices toward the return path. In a sinking output, the load is connected to the positive supply, and the sink module provides the path to ground. When the output is active, current travels from the supply, through the field device, and into the sink module to ground. That means the current leaves the field device, i.e., it flows out of the field device.

If the system were a sourcing output, the current would flow out of the module into the field device (current flows into the field device). The ideas that no current flows or that current circulates freely don’t describe a powered sinking path; there is a defined path for current to return to ground when the load is energized.