What changes between the two windings in a transformer?

• A. Voltage and Current
• B. Coil Color
• C. Wire Gauge
• D. Physical Size

Answer: (A)

A transformer changes the electrical quantities between its two windings through electromagnetic induction. The voltage on the secondary winding is determined by the turns ratio: more turns in the secondary mean a higher voltage, and fewer turns mean a lower voltage, relative to the primary. Because power is conserved (in an ideal transformer), the current in the secondary adjusts inversely with the voltage: if the secondary voltage goes up, the secondary current goes down, and if the voltage goes down, the current goes up. So the actual change between the windings is in voltage and current. Coil color, wire gauge, and physical size don’t define the transformation itself—color is cosmetic, gauge affects current capacity, and size relates to power handling rather than the fundamental voltage-current change.