Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Which of the following does not change in a transformer?
Current
Voltage
Frequency
All of the above
Frequency
A transformer is a static electromagnetic device that transfers electrical energy between two or more circuits through electromagnetic induction. Throughout this energy transfer process, the frequency of the alternating current remains invariant.
A transformer is a static electromagnetic device that transfers electrical energy between two or more circuits through electromagnetic induction. Throughout this energy transfer process, the frequency of the alternating current remains invariant.
E=4.44fN╬жmтАЛ тАФ EMF equation where f is frequency
V2тАЛV1тАЛтАЛ=N2тАЛN1тАЛтАЛ=I1тАЛI2тАЛтАЛ тАФ Ideal transformer transformation ratio
The transformer operates on Faraday's Law of Electromagnetic Induction and Lenz's Law. When an AC voltage V1тАЛ is applied to the primary winding, it creates a time-varying magnetic flux ╬ж in the core. Since the induced EMF E2тАЛ in the secondary winding depends directly on the rate of change of this flux (e=тИТNdtd╬жтАЛ), the frequency component of the flux, which is dictated by the supply source, is transferred to the secondary side without alteration.
Transformers are constant flux machines.
Input and output frequencies are synchronized at the supply frequency.
Voltage and current levels are modified based on the turns ratio.
The core material is designed to handle the specific supply frequency.
Efficient power transmission over long distances.
Enables impedance matching in electronic circuits.
Cannot operate on DC supply (as dtd╬жтАЛ=0).
Losses occur due to hysteresis and eddy currents in the core.
Power grid voltage step-up/step-down.
Galvanic isolation in sensitive electronic equipment.
Standard power frequency in India is 50 Hz.
Option A (Current) changes based on the turns ratio (I2тАЛ=I1тАЛN2тАЛN1тАЛтАЛ).
Option B (Voltage) changes based on the turns ratio (V2тАЛ=V1тАЛN1тАЛN2тАЛтАЛ).
C is correct тАФ The frequency remains unchanged because the transformer relies on the source-driven time-varying magnetic flux to induce voltage, and the rate of flux change is determined by the source frequency.
Always remember that transformers are 'static' devices, meaning no moving parts, and they are incapable of changing the frequency of the electrical energy they process.