28/05/2025
The working principle of a transformer is based on Faraday’s Law of Electromagnetic Induction, which states that a change in magnetic flux in a coil induces an electromotive force (EMF) in another nearby coil.
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🔧 Basic Working Principle
A transformer transfers electrical energy from one circuit to another through electromagnetic induction, without any physical connection between the two circuits. It works only on alternating current (AC).
⚙️ Key Components
Primary Winding: Connected to the input AC supply.
Core: Usually made of laminated soft iron to provide a low-resistance path for magnetic flux.
Secondary Winding: Connected to the output load.
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⚡ Step-by-Step Operation
1. AC Input is applied to the primary winding.
2. This creates an alternating magnetic flux in the core.
3. The magnetic flux links to the secondary winding through the core.
4. According to Faraday’s Law, this changing flux induces an EMF in the secondary winding.
5. If the secondary circuit is closed, current flows and power is transferred.
🔄 Voltage Transformation
The voltage and current relationship depends on the turns ratio:
\frac{V_s}{V_p} = \frac{N_s}{N_p}
Where:
, : Secondary and primary voltages
, : Number of turns in secondary and primary windings
Step-up Transformer: → Output voltage is higher.
Step-down Transformer: → Output voltage is lower.
