What is the effect of reversing polarity when measuring current with a DVOM?

• A. It will show a negative reading
• B. It will burn out the meter
• C. It will show the same reading as normal
• D. It will flash zero

Answer: (A)

When you measure DC current with a DVOM, the meter uses a shunt with a defined orientation to establish a reference direction. If the current flows in the same direction as that reference, you get a positive reading. If you swap the test leads, the same current is now referenced in the opposite direction, so the display shows a negative value. The magnitude stays the same; the sign simply indicates the direction of current relative to how the leads are connected. For AC current, polarity isn’t meaningful, but in DC measurements that rely on lead orientation, reversing the leads will produce a negative reading rather than the same positive value.