Which instrument measures voltage, current, and resistance?

• A. Oscilloscope
• B. Caliper
• C. Thermometer
• D. Multimeter

Answer: (D)

A multimeter is the tool that can measure voltage, current, and resistance. It works by offering separate settings for each quantity: voltage mode lets you read the potential difference across two points (DC or AC), current mode requires placing the meter in series with the circuit to measure the flow of charge, and resistance mode (ohms) measures how much a component resists current when the circuit is powered off. This versatility makes it the go-to instrument for basic robotics troubleshooting—checking battery voltage, motor current draw, and resistor values all with one device. An oscilloscope can display voltage over time and help analyze signals, but it isn’t primarily used to read resistance and, for current, needs special probes or setups. Calipers measure physical dimensions, and thermometers measure temperature, not electrical properties.