If a transformer outputs voltage without load but the voltage disappears when connected, what is the likely issue?

The scenario describes a transformer that outputs voltage under no load conditions but fails to maintain that voltage when a load is applied. This typically indicates a problem with either the load itself or the transformer.

When a load is connected, if the transformer cannot sustain voltage, it often points to a shorted load or a damaged transformer. A shorted load presents very low resistance, causing the transformer to be unable to supply the necessary current, leading to a voltage drop. Similarly, if the transformer is damaged—such as having internal faults—it may not perform correctly under load, resulting in a voltage drop or complete loss of voltage.

In contrast, the other choices may not accurately identify the root cause of the described behavior. A faulty circuit generally would cause issues regardless of load, incorrect voltage ratings would likely prevent the transformer from operational voltage even without load, and a broken connection would likely mean no voltage present at all rather than a drop under load. Thus, the most logical conclusion for the observed behavior is that the issue lies in either a shorted load or damage within the transformer itself.