What does a sinking circuit do?

• A. Provides ground for an electrical load.
• B. Provides supply voltage to a load.
• C. Stores energy in a capacitor.
• D. Converts AC to DC.

Answer: (A)

A sinking circuit provides a path to ground for current, completing the circuit by pulling current down to 0 V. That means its job is to give a ground return for a load: the load is connected to a positive supply, and when the sinking element is activated, current flows from the supply through the load into the sinking device and to ground.

The other functions described don’t fit sinking: providing supply voltage to a load is a sourcing action, not sinking; storing energy in a capacitor is energy storage, not a current path to ground; and converting AC to DC is rectification, not a ground return role.