I found several transformers on digikey. I have one quick question: I understand the significance of the turns ratio, but when a manufacturer publishes a voltage for the primary and secondary winding, is this a maximum voltage or the exact voltage that must exist across the winding.
In other words, if the primary winding has a voltage rating of 5 v and the secondary winding has a voltage rating of 1 v, does this mean the voltage step down is 5:1 or that 5 v must exist across the primary winding?