Eddy currents in the core of transformer can't be developed by

Options

A. increasing the number of turns in secondary coil
B. taking laminated transformer
C. making step down transformer
D. using a weak a.c at high potential

Answer

To solve the question regarding the development of eddy currents in the core of a transformer, we will analyze the factors that contribute to the generation of these currents and identify the option that does not contribute to their development.

### Step-by-Step Solution:

1. **Understanding Eddy Currents**: Eddy currents are loops of electrical current that are induced within conductors by a changing magnetic field. According to Faraday's law of electromagnetic induction, a changing magnetic field within a closed loop induces an electromotive force (EMF) in the conductor.

2. **Role of Magnetic Field**: In a transformer, the alternating current (AC) in the primary coil creates a varying magnetic field. This varying magnetic field is essential for inducing EMF in the secondary coil, but it also leads to the generation of eddy currents in the core material.

3. **Eddy Current Formation**: Eddy currents are formed when there is a change in magnetic flux through a conductor. The magnetic flux (Φ) can be expressed as the integral of the magnetic field (B) over the area (A) through which it passes:
\[ Φ = \int B \cdot dA \]
When the magnetic field varies, the flux changes, leading to the generation of eddy currents.

4. **Minimizing Eddy Currents**: To reduce the formation of eddy currents in the transformer core, manufacturers use laminated cores. Laminating the core involves using thin sheets of magnetic material insulated from each other, which restricts the flow of eddy currents and minimizes energy losses.

5. **Identifying the Correct Option**: The question asks for the method that does not develop eddy currents. Since laminating the core is a method used to reduce eddy currents, it cannot be a method that develops them. Thus, the correct answer to the question is:
- **Option B: Laminated Transformer** (as it minimizes eddy currents).

### Conclusion:
Eddy currents in the core of a transformer cannot be developed by laminating the core. Instead, laminating is a technique used to reduce these currents and improve the efficiency of the transformer.