What is an open circuit?

• A. A closed loop that allows current to flow normally.
• B. A break in the circuit preventing current flow.
• C. A device that stores electrical energy.
• D. A circuit with short to supply and ground.

Answer: (B)

An open circuit is when there’s a break in the conducting path so electrons can’t complete a loop from the power source to the load. Because the circuit isn’t closed, current has no continuous path to follow, so the current is essentially zero even though a voltage source is present. This can happen if a switch is open, a wire is broken, or a component isn’t connected. You might see a voltage difference across the gap, but no current flows. In contrast, a closed loop allows current to flow; a device that stores energy isn’t about openness; and a short to supply and ground is a different fault that creates a very low-resistance path.