Keiko builds a transformer in the lab, but it does not decrease the voltage as much as she needs. What should Keiko change to further reduce the voltage?

A transformer’s voltage ratio depends on the turns ratio: the secondary voltage decreases when the primary winding has more coils than the secondary winding. Increasing the number of coils in the primary winding makes that ratio smaller and reduces the output voltage further. Increasing the secondary coils would raise the output voltage instead.

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