Electronic – What exactly is a short circuit


In my book there is no explanation of the phrase short circuit but at many places the author has used it. I had googled it. Some explain it as the flow of charge along a high potential difference while others explain it as the flow of charge along a low resistance path. What exactly is a short circuit? An explanation along with a diagram would be very helpful.

Best Answer

In simple and practical terms, a short circuit is an unwanted or unintentional path that current can take which bypasses the routes you actually want it to take.

This is normally a low resistance path between two points of differing potential.

For instance:


simulate this circuit – Schematic created using CircuitLab

In the left simple LED circuit, just over 6 mA is flowing round the circuit. Create a short circuit, represented by a very low resistance (no wire is a perfect 0 Ω conductor) and 5000 A wants to try to flow through it. That's bad news for the battery. The battery could well explode. What is certain, though, the internal resistance of the battery will limit the current that can exist and a large voltage drop will be seen at the terminals of the battery causing the whole circuit to stop functioning.