If a transmitter is malfunctioning and you check across its positive and negative terminals with a multimeter, what should be your next step?

In the scenario where a transmitter is malfunctioning and you've already measured voltage across its positive and negative terminals with a multimeter, getting in series with the loop is a logical next step. When a transmitter is underperforming or not providing the expected output, inserting a series measurement allows for a more accurate assessment of the current flowing through the loop.

This approach helps in diagnosing whether the issue lies within the transmitter itself or if there is an open circuit or excessive resistance elsewhere in the system that is affecting its performance. By measuring the current, you can determine if the transmitter is receiving adequate power and whether it’s functioning correctly by producing the expected current output in its designated operational range.

This method effectively helps isolate faults and ensures that the diagnosis is being made based on real-time data from the actual operating conditions of the loop. If problems are detected while measuring in series, further investigation into the transmitter’s condition and the entire loop circuitry can be guided more effectively.

In this case, the other choices may not provide the immediate insight needed based on current readings and could lead to unnecessary replacements or checks in diagnostics.