In a circuit, what must happen for current to flow?

For current to flow in a circuit, a voltage is essential. Voltage acts as the driving force that pushes electrons through a conductive material. It creates an electric potential difference between two points in the circuit, effectively enabling current to travel from the high potential area to the low potential area. This potential difference is what causes electric charges to move, thereby generating current.

While resistance is also a component of electrical circuits, it does not need to be present for current to flow; instead, it influences how much current will flow for a given voltage according to Ohm's Law. Similarly, the notion of a short circuit, which occurs when unintended paths allow current to flow, does not inherently relate to the requirement for current flow—it highlights a specific circumstance rather than the fundamental requirement of voltage. Lastly, having no interruption could imply continuity in the circuit, but it does not negate the necessity of voltage itself. Without voltage, regardless of these other factors, there will be no movement of current. Thus, the presence of voltage is fundamental for current to flow through a circuit.