What device is commonly used to measure current, voltage, and resistance in a circuit?

The correct answer is a multimeter, which is a versatile device designed to measure multiple electrical properties, including current, voltage, and resistance. A multimeter can be either analog or digital and provides the user with the ability to perform various measurements in a single device, making it essential for anyone working on electrical circuits.

When measuring current, a multimeter can be connected in series with the circuit. To measure voltage, it connects in parallel across the component of interest. For resistance measurements, the multimeter sends a small current through the resistor and measures the voltage drop, allowing it to calculate the resistance using Ohm's law.

The versatility of the multimeter enables it to serve as both a voltmeter (for measuring voltage) and an ammeter (for measuring current) while also incorporating resistance measurement capabilities, thereby making it a comprehensive tool for circuit analysis.

In contrast, an oscilloscope is specifically used for observing the changing signals in a circuit, typically providing a visual representation of voltage over time, but it does not measure resistance directly. A voltmeter specializes in measuring voltage only, while an ammeter is focused solely on measuring current. Thus, none of these other tools offer the same range of functionality as a multimeter.