Which of the following best describes a short circuit?

• A. A path of very low resistance that causes excessive current, bypassing the load
• B. A circuit with high resistance
• C. A broken conductor that stops current
• D. An open circuit

Answer: (A)

A short circuit is a path of very low resistance that bypasses the load the circuit is meant to power. Because the resistance of this alternate path is so small, most of the current flows through it rather than through the intended device. As a result, the current skyrockets according to Ohm’s law (I = V/R), which can cause overheating, damage to components, or trip a fuse or breaker. The load ends up receiving little to no current, which is why devices may fail to operate during a short.

This is different from a circuit with high resistance, where the current is naturally limited and the load may not operate properly. It’s also different from an open circuit, where a break prevents any current from flowing at all. A short circuit still provides a complete, low-resistance path for current, but with much less resistance than the normal load.