Question

Why in 1-Ø transformer, the primary and secondary currents and voltages differ in terms of magnitude only?​

Answer 1

Answer:

A transformer primary having more turns than its secondary is generally only true of a Step-down transformer.

The turns of the voltage of the primary divided by the turns of the primary sets the volts/turn constant. For example, a primary of 120 turns and 120V has a 1V/T constant so if you want 12V out, the secondary will need 12T. But what if you need power for a cold cathode lamp that requires 1200V? Then your secondary will need 1200T. This last example would be called a Step-up transformer.

There is also a case where the primary and secondary have the same number of turns: An Isolation transformer has the same voltage out as in and is used to provide isolation from the mains power system.