What must be done before using an ohm meter?

Using an ohm meter requires specific procedures to ensure accurate measurements and safety. The correct action is to remove power from the circuit and isolate the component. This is crucial because if there's any voltage present in the circuit while measuring resistance, it can lead to incorrect readings and potentially damage the meter.

Isolating the component means disconnecting it from the circuit, which ensures that the resistance measurement is only of the component itself, without interference from other components or power sources. By adhering to this practice, you guarantee both the accuracy of your measurement and the safety of your testing equipment.