What is the purpose of the COM terminal across all measurements?

• A. It powers the device
• B. It measures resistance
• C. It serves as the return path for measurements
• D. It calibrates the display

Answer: (C)

In measurement circuits, you always need a complete loop and a common reference point. The COM terminal serves as that common return path for the measurement signals, acting as the reference or ground for all readings. When you connect the probes, one lead provides the test signal and the other returns through COM, creating the closed path the meter needs to sense voltage, resistance, or current. This return path ensures a stable, reference-based measurement across any range or mode. It isn’t about powering the device, it isn’t the act of measuring resistance by itself, and it isn’t a calibration function.