All values of a transformer are proportional to its:

The correct answer is the turns ratio because a transformer operates on the principle of electromagnetic induction, where the voltage and current on the primary and secondary sides are related by the ratio of the number of turns of wire in the primary coil to the number of turns in the secondary coil. This relationship is fundamental to how transformers step up or step down voltages.

The turns ratio determines not only the voltages across the primary and secondary but also directly affects the transformer's current capability. For example, if the turns ratio indicates that the transformer steps down voltage, the current on the secondary side will proportionally increase according to the conservation of power principle (neglecting losses). This means all significant electrical values within a transformer can be derived from or are dependent on its turns ratio, making it essential for understanding and predicting transformer behavior.

Physical size, input power, and load current, while related to the overall design and function of a transformer, do not universally dictate the proportionality of all values. For instance, two transformers could be of different physical sizes but have the same turns ratio, resulting in identical voltage transformation characteristics. The same applies to input power and load current. Thus, the turns ratio remains the key factor tying together all the transformation characteristics of a