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A transformer transforms
Voltage
Current
Power
Frequency
Power
A transformer is a static electromagnetic device that transfers electrical energy from one circuit to another through magnetic coupling, maintaining the same frequency. While it changes the magnitude of voltage and current levels to optimize transmission or usage, it does not transform power itself, as the input power is essentially equal to the output power (neglecting losses).
A transformer is a static electromagnetic device that transfers electrical energy from one circuit to another through magnetic coupling, maintaining the same frequency. While it changes the magnitude of voltage and current levels to optimize transmission or usage, it does not transform power itself, as the input power is essentially equal to the output power (neglecting losses).
PinтАЛ=V1тАЛI1тАЛcos╧Х1тАЛ
V1тАЛI1тАЛтЙИV2тАЛI2тАЛ
V2тАЛV1тАЛтАЛ=N2тАЛN1тАЛтАЛ=I1тАЛI2тАЛтАЛ
The transformer operates on Faraday's Law of Electromagnetic Induction and mutual induction between two coils wound on a common magnetic core. When an alternating current flows through the primary winding, it creates a time-varying magnetic flux that links the secondary winding, inducing an electromotive force (EMF) based on the turns ratio.
Operates strictly on AC supply; DC will lead to excessive current due to zero reactance.
Frequency remains constant throughout the transformation process.
Efficiency is defined as the ratio of output power to input power, typically > 95%.
Acts as an impedance matching device.
Enables efficient long-distance power transmission via high voltage step-up.
Provides electrical isolation between primary and secondary circuits.
Cannot operate on DC power sources.
Subject to various losses like hysteresis, eddy current, and copper losses.
Power grid distribution and transmission.
Impedance matching in communication systems.
Voltage regulation in electronic appliances.
The question statement is technically 'A transformer transforms voltage/current levels' while keeping power constant.
Option D is wrong because transformers are defined by their inability to change frequency.
The term 'transform' in engineering often refers to changing parameters (V and I) while conserving total energy.
C is correct тАФ A transformer is an energy transfer device that changes voltage and current levels at a constant frequency without transforming power.
In competitive exams, remember that transformers are constant-power (mostly) and constant-frequency devices; if any question suggests changing frequency, it is always incorrect.