How does a step-up transformer change voltage and amperage?

How does a step-up transformer change voltage and amperage?

• A. Voltage is decreased, and amperage is increased proportionally
• B. Voltage is increased, and amperage is decreased proportionally
• C. Both voltage and amperage are increased
• D. Voltage remains constant, and amperage is decreased

Answer: (B)

A step-up transformer is designed to increase voltage while decreasing current. When alternating current (AC) flows through the primary coil of the transformer, it generates a magnetic field that induces a higher voltage in the secondary coil. This occurs according to the principle of electromagnetic induction, which states that the voltage across the coils is related to the ratio of the number of turns of wire in each coil.

As voltage increases, the power (which is the product of voltage and current) must remain constant in an ideal transformer, assuming no energy losses. Therefore, when the voltage is stepped up, the current in the secondary winding must decrease proportionally to maintain that constant power. This relationship reflects the conservation of energy in electrical systems, where higher voltage results in a corresponding decrease in current to keep power levels stable.

This principle is fundamental in applications like radiography, where transformers are used to achieve the high voltages needed for X-ray production while managing the current to ensure safety and efficiency.