What instrument is used to measure voltage, current, and resistance?

• A. A megohmmeter
• B. A multimeter
• C. A clamp-on ammeter
• D. An oscilloscope

Answer: (B)

A multimeter is the instrument designed to measure voltage, current, and resistance in one device. It can be digital or analog and handles both AC and DC measurements in most models. To measure voltage, you place the probes across the component or power source and read the reading in voltage mode. To measure current, you typically break the circuit and insert the meter in series so the current flows through it, then read amperes. To measure resistance, you first power down the circuit and place the probes across the component; the meter sends a small current and determines resistance from the measured response.

Safety notes: ensure power is off when measuring resistance, select the appropriate range, and use the meter’s fuses to protect you and the instrument. Other tools have narrower functions—megohmmeters test insulation resistance at high voltages, clamp-on ammeters measure current without breaking the circuit (and usually don’t measure voltage or resistance in a single reading), and oscilloscopes visualize voltage waveforms (sometimes with current probes) but don’t directly measure resistance. That versatility is what makes a multimeter the best answer.