A transformer whose secondary or output voltage is lower that its input or primary voltage is called a step-________ transformer.

A transformer whose secondary or output voltage is lower that its input or primary voltage is called a step-________ transformer.

• A. Up
• B. Down
• C. Auto
• D. Buck

Answer: (B)

When the output voltage is lower than the input, the transformer is called a step-down transformer. This happens because the voltage transfer depends on the turns ratio: V_secondary = (N_secondary / N_primary) × V_primary. If the secondary has fewer turns than the primary, the ratio is less than one, so the secondary voltage is reduced. Energy balance means the current on the secondary must increase to deliver the same power to the load, within losses. This is the standard way to safely lower high distribution voltages to usable levels for equipment. The other terms don’t fit this situation: a step-up transformer would have a higher secondary voltage than the primary, an auto-transformer uses a single winding in a way that can both step up or down but isn’t the typical step-down description, and buck refers to a DC power-conversion concept rather than a transformer type.

When the output voltage is lower than the input, the transformer is called a step-down transformer. This happens because the voltage transfer depends on the turns ratio: V_secondary = (N_secondary / N_primary) × V_primary. If the secondary has fewer turns than the primary, the ratio is less than one, so the secondary voltage is reduced. Energy balance means the current on the secondary must increase to deliver the same power to the load, within losses. This is the standard way to safely lower high distribution voltages to usable levels for equipment. The other terms don’t fit this situation: a step-up transformer would have a higher secondary voltage than the primary, an auto-transformer uses a single winding in a way that can both step up or down but isn’t the typical step-down description, and buck refers to a DC power-conversion concept rather than a transformer type.