What is the term for a sensor output that sinks current from the load when active?

• A. Current sourcing
• B. Current sinking
• C. Voltage output
• D. Open-collector

Answer: (B)

Understanding sinking versus sourcing outputs helps explain what happens when a sensor is active. When the sensor is active, it provides a path to ground for the current, pulling current from the supply through the load and into the sensor. That behavior is called current sinking. In automation, sinking outputs pull current down to ground, whereas sourcing outputs push current from the supply toward the load. Open-collector is a hardware arrangement that can perform sinking, but the general term for the described behavior is current sinking. A voltage output refers to the signal type, not the current path, and current sourcing would be the opposite behavior.