When checking the output voltage of a transformer, it is important to ensure it is connected to which of the following?

When checking the output voltage of a transformer, it is crucial to ensure it is connected to the load. This is because the output voltage of a transformer can vary based on the load it is supplying. When the transformer is under load, it provides a more accurate representation of its operational performance. If the transformer is tested without a load, the voltage reading may not reflect the actual conditions under which the transformer operates during normal use.

Using the proper load helps determine whether the transformer is functioning correctly and maintaining the expected voltage levels. It is common for transformers to experience voltage drops or fluctuations when loaded due to their inherent internal impedance. Therefore, measuring output voltage with the load connected ensures that the readings reflect real-world operational conditions, helping technicians identify any potential issues with the transformer or load performance.