Step-Up Transformer Practice Quiz

A step-up transformer increases the voltage while decreasing the current. This occurs to conserve power (ignoring losses) according to the principle of energy conservation.

A transformer's main function is to change (step up or step down) the voltage level in an AC circuit via electromagnetic induction. It accomplishes this without converting electrical energy into any other form.

In an ideal transformer, the power on the primary side equals the power on the secondary side since energy is conserved. This assumes there are no losses in the system.

Ohm's law states that Voltage = Current x Resistance, making it a fundamental tool for analyzing electrical circuits. It directly relates these three key parameters and is essential for understanding circuit behavior.

Transformers rely on a changing magnetic field to induce voltage across coils, which necessitates the use of alternating current (AC). Direct current does not produce a continuously varying magnetic field and thus is not suitable for transformer operation.

The voltage in a transformer is directly proportional to the number of turns in the winding. With 200 turns in the secondary compared to 100 in the primary, the secondary voltage is double the primary voltage.

Transformers operate based on electromagnetic induction, where a changing magnetic field induces a voltage in a nearby coil. This fundamental concept is encapsulated in Faraday's law of induction.

Isolation between the coils ensures that voltage is transferred solely through electromagnetic induction. This design avoids any direct electrical connection, which enhances safety and proper functioning of the transformer.

In an ideal transformer, the product of voltage and current (which represents power) remains constant. This means that any increase in voltage results in a proportional decrease in current, thereby conserving power.

A higher number of turns in the secondary coil increases the voltage output relative to the primary coil, as given by the turn ratio. This results in a higher voltage and a lower current when power is conserved in an ideal transformer.

Transformers are used to step up the voltage for long-distance transmission, which reduces current and minimizes resistive losses. They then step down the voltage for safe usage at the consumer end, thus ensuring efficient power distribution.

Because power is conserved in an ideal transformer, tripling the voltage requires that the current be reduced by the same factor to maintain constant power. This inverse relationship is a fundamental aspect of transformer operation.

In an ideal transformer, the frequency of the alternating current remains constant on both the primary and secondary sides. While voltage and current adjust according to the turns ratio, the AC frequency is maintained by the power source.

The transformer ratio is defined by the relationship between the number of turns in the primary and secondary coils. Increasing the secondary turns increases the overall ratio, resulting in a higher output voltage in a step-up transformer.

Even with an open secondary, the transformer draws a small magnetizing current in the primary winding in order to maintain its magnetic field. This current is much lower than a full load current and is a normal aspect of transformer operation.

The efficiency of a transformer largely depends on the quality of its core material and construction, which affect losses such as hysteresis and eddy current losses. A well-designed core minimizes these losses, thereby enhancing overall transformer performance.

Real-world transformers face efficiency reductions mainly due to resistive losses in the windings (copper losses) and eddy current losses in the core material. These factors cause a deviation from the ideal power conservation scenario.

Using the conservation of power in an ideal transformer, the input power (primary) must equal the output power (secondary). With a secondary power of 240V x 2A = 480W, the primary current is calculated as 480W / 120V = 4 A.

Eddy currents are induced circulating currents in the transformer's core that result in energy loss. Laminating the core disrupts these currents by creating thin layers, which significantly reduces eddy current losses and improves efficiency.

Even without a load, a transformer draws a small magnetizing current to maintain the magnetic flux in its core. This current remains minimal and relatively constant, as it is only required to overcome core losses and does not represent a load condition.