Regarding transformer phase relationships, which statement is most accurate about the output phase of the secondary relative to the primary?

Introduction / Context:
In many transformer applications—such as multi-secondary power supplies, audio coupling, and feedback networks—the instantaneous polarity (phase) of the secondary relative to the primary matters. Designers use this knowledge to connect windings series-aiding or series-opposing and to ensure correct rectifier phasing.

Given Data / Assumptions:

• Ideal transformer model for conceptual clarity.
• Standard dot notation on schematics denotes corresponding ends of windings.
• Supply frequency remains constant and appropriate for the core.

Concept / Approach:
The phase of the induced secondary voltage is determined by the winding sense (direction of turns) relative to the primary. If the dotted ends are treated as corresponding ends, a positive rise at the dotted primary end produces a simultaneous positive rise at the dotted secondary end. Thus, phase can be 0 degrees (in phase) or 180 degrees (out of phase) depending on how the windings are oriented or connected; it is not intrinsically set by frequency.

Step-by-Step Solution:
Identify polarity dots on the schematic.If primary dotted terminal becomes positive relative to its undotted terminal, the secondary dotted terminal becomes positive relative to its undotted terminal at the same instant.Therefore, output phase depends on the winding direction/connection.

Verification / Alternative check:
Using an oscilloscope and a low-voltage test, probe primary and secondary dotted ends simultaneously. The waveforms rise together when the dots correspond to in-phase ends.

Why Other Options Are Wrong:
Always in phase or always out of phase is an overgeneralization; either can occur based on winding orientation.

Dependence on frequency for phase inversion is incorrect; frequency affects magnitude and core behavior, not the instantaneous polarity mapping.

Random phase is false; dot notation removes ambiguity.

Common Pitfalls:
Ignoring dot notation and assuming schematic placement (left/right) implies phase. Only the dots or documented lead designation define the relationship.

Final Answer:
dependent on the direction of the primary and secondary windings