The turn's ratio of the step-down transformer with dual voltage secondary shown in figure "B" of the illustration is two to one (total). If 220 volts were applied to terminals 'H1' and 'H2', what would be measured across 'X3' and 'X4'? Illustration EL-0082
• Transformer turns ratio and how it relates primary voltage to secondary voltage • How a dual-voltage secondary can be wired in series or parallel • Which secondary terminals in figure B are actually the ends of the entire secondary winding vs. taps or junctions
• Start from the 2:1 turns ratio and calculate the total secondary voltage when 220 V is applied to the primary • Look closely at figure B and decide whether X3–X4 represents the full secondary, only half of it, or a junction plus an end • Compare what the voltage would be across half of the secondary vs. across the full secondary and match those values to the answer choices
• Confirm which terminals in figure B are electrically tied together inside the transformer (the crossover connection) • Determine whether X3 is a tap/junction between two equal secondary halves or an end of a winding • After you compute the expected voltage, check that it is consistent with a 2:1 step-down transformer (the secondary must be lower than 220 V, not higher)
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