*Question T7D11:
Which of the following precautions should be taken when measuring in-circuit resistance with an ohmmeter?*  

*Correct Answer is  B: Ensure that the circuit is not powered*  

### AI Response: (may contain errors)  

When measuring in-circuit resistance with an ohmmeter, the most important precaution is to ensure that the circuit is not powered. Here's a breakdown of why this is crucial and why the other options are incorrect:

### Correct Answer: B - Ensure that the circuit is not powered
- **Explanation**: An ohmmeter applies a small voltage to measure resistance. If the circuit is powered, the voltage from the circuit can interfere with the ohmmeter's measurement, potentially damaging the meter and providing inaccurate readings. Always disconnect power before measuring resistance to ensure safety and accuracy.

### Why the Other Choices are Incorrect:
- **A: Ensure that the applied voltages are correct**
  - **Explanation**: This is not relevant when using an ohmmeter because the ohmmeter itself generates its own voltage to measure resistance. The applied voltages in the circuit do not need to be correct or even present.

- **C: Ensure that the circuit is grounded**
  - **Explanation**: While grounding is important for safety in many electrical measurements, it is not a specific requirement for measuring resistance with an ohmmeter. The key concern is that the circuit must be powered off, not necessarily grounded.

- **D: Ensure that the circuit is operating at the correct frequency**
  - **Explanation**: Resistance measurements are not frequency-dependent. An ohmmeter measures DC resistance, and the frequency of operation is irrelevant when measuring resistance in a circuit.

### Summary
- Always ensure the circuit is powered off before measuring resistance with an ohmmeter to avoid damage and ensure accurate readings. The other options do not apply to the process of measuring resistance with an ohmmeter.