What is an open circuit?

• A. A break that stops current flow
• B. A continuous path for current
• C. A short to ground
• D. A ground fault

Answer: (A)

An open circuit means the electrical path is interrupted, so current cannot complete a loop. For current to flow, there must be a continuous path from the power source, through the conductors and load, back to the source. When there’s a break—like a disconnected connector, a damaged wire, or a switch left open—the loop isn’t complete, and devices on that branch won’t operate because no current can travel. This differs from a closed circuit, which has a complete path; a short to ground, which is a low-resistance unintended path to ground causing excessive current; and a ground fault, which is current leaking to ground due to insulation failure. So the break that stops current flow is the essence of an open circuit.