When measuring resistance with a multimeter, what is the recommended action?

When measuring resistance with a multimeter, it is necessary to de-energize the circuit before making the measurement. This is crucial because applying the multimeter to a powered circuit can lead to inaccurate readings and potentially damage the meter. Resistance measurements require an open circuit since the multimeter produces its own small current to measure resistance.

If the circuit is still energized, the presence of voltage can cause interference with the multimeter's internal measurement processes, leading to erratic readings or even risks of electric shock to the technician. Therefore, ensuring that the circuit is de-energized is a key safety practice and essential for obtaining accurate resistance measurements. This ensures the multimeter operates properly and safely, allowing for reliable diagnostics and maintenance of electrical components.