If resistor R(3) is disconnected at terminal D, what will the ohmmeter read?

If resistor R(3) is disconnected at terminal D, what will the ohmmeter read?

• A. Infinite resistance
• B. 3 ohms
• C. 0 ohms
• D. 10 ohms

Answer: (A)

An ohmmeter determines resistance by forcing a small current through the path between its leads and reading the resulting current. If any part of that path is open—such as resistor R(3) being disconnected at terminal D—the circuit isn’t complete, so no current can flow. That makes the measured resistance extremely large, effectively infinite, which shows there is no conductive path between the ohmmeter’s probes. If the resistor were properly connected, you’d see its actual value (for example, a few ohms), and a direct short would read near zero. So, when R(3) is disconnected, the reading is infinite resistance.

An ohmmeter determines resistance by forcing a small current through the path between its leads and reading the resulting current. If any part of that path is open—such as resistor R(3) being disconnected at terminal D—the circuit isn’t complete, so no current can flow. That makes the measured resistance extremely large, effectively infinite, which shows there is no conductive path between the ohmmeter’s probes. If the resistor were properly connected, you’d see its actual value (for example, a few ohms), and a direct short would read near zero. So, when R(3) is disconnected, the reading is infinite resistance.