ARRL Technician Practice Exam

Which of the following might damage a multimeter?

1. Measuring temperature in an oven

2. Using it in a wet environment

3. Attempting to measure voltage when using the resistance setting

4. Measuring capacitance

The correct answer is: Attempting to measure voltage when using the resistance setting

The ability to damage a multimeter can happen when it is used incorrectly, and one such incorrect use is attempting to measure voltage while the device is set to the resistance (ohms) setting. When a multimeter is in resistance mode, it sends a small current through the circuit to determine the resistance value. If you then attempt to measure voltage in the same configuration, you create a conflict in the operation of the device. Measuring voltage requires the multimeter to be in voltage mode, where it is designed to read the potential difference without introducing current into the circuit. If you inadvertently switch to measure voltage while the multimeter is set to resistance mode, it could lead to internal damage, as the device is not built to handle voltage under that setting. This situation could destroy sensitive components or lead to incorrect readings. Other scenarios presented, such as measuring temperature in an oven, using the meter in a wet environment, or measuring capacitance, do not inherently damage the multimeter when used correctly. Multimeters typically have specialized settings for these measurements, and as long as the correct mode is used, they should function safely and effectively. Therefore, the risk of damage is specifically associated with the incorrect setting for measuring voltage while in resistance mode.