Electronic Technician (ET) Apprentice Technical Training (ATT) Comprehensive Practice Test

In a step-up transformer, what is typically true about the turns ratio?

The secondary has fewer turns than the primary

Both primary and secondary have the same number of turns

The secondary has more turns than the primary

In a step-up transformer, the primary function is to increase voltage from the primary side to the secondary side. This is achieved through the relationship defined by the turns ratio of the transformer. Specifically, the turns ratio is the number of turns in the secondary coil divided by the number of turns in the primary coil.

In the case of a step-up transformer, the secondary winding has more turns than the primary winding. This is crucial because, according to the transformer's properties described by the equation $ V_s / V_p = N_s / N_p $, where $ V_s $ is the secondary voltage, $ V_p $ is the primary voltage, $ N_s $ is the number of secondary turns, and $ N_p $ is the number of primary turns. When $ N_s $ is greater than $ N_p $, the secondary voltage $ V_s $ becomes greater than the primary voltage $ V_p$, effectively stepping up the voltage.

Thus, it is essential for the secondary to have more turns than the primary in a step-up transformer, confirming that the correct answer is indeed the indication of a greater number of turns in the secondary coil compared to the primary coil. This relationship is fundamental to understanding how transformers

The turns ratio does not affect voltage