How does a multimeter function?

A multimeter is a versatile tool used in electrical diagnostics and troubleshooting, capable of measuring various electrical parameters. The correct answer highlights its ability to measure voltage, current, and resistance within a circuit, which are fundamental electrical characteristics.

When measuring voltage, the multimeter can identify the potential difference between two points in a circuit, allowing users to assess whether the voltage levels are within acceptable ranges. For current, the multimeter can be configured to measure both direct current (DC) and alternating current (AC), giving insight into how much electrical flow is occurring. Additionally, measuring resistance helps determine the integrity of components and circuits by identifying short circuits or open connections.

In contrast, the other choices represent more limited or specific functions. A multimeter does not measure only current, and it is not solely a tool for visual representation of electrical signals nor is it specialized exclusively for testing insulation resistance of wires. While insulation resistance testing can be done using specific multimeter functions (or dedicated insulation testers), it does not encompass the full range of the multimeter's capabilities.