Which secondary winding of a transformer will have the highest measured DC resistance if three windings produce 5.0 volts, 12.6 volts, and 150 volts?

The secondary winding of a transformer that has the highest measured DC resistance is typically the one with the highest voltage rating. This phenomenon occurs due to the way wire gauge is selected for each winding.

Higher voltage windings are often constructed using thinner wire, which increases the resistance of the winding. In this scenario, the winding producing 150 volts would likely have a higher resistance compared to the lower voltage windings. This is because, to maintain insulation and prevent arcing at higher voltages, thinner wire may be used in the higher voltage winding.

On the other hand, the lower voltage windings, like the ones producing 5.0 volts and 12.6 volts, can use thicker wire, which reduces resistance. Therefore, the 150 volt winding is expected to have the highest measured DC resistance.