The transformation ratio K of an isolation transformer is _________. 

Explanation:

Isolation Transformer

Definition: An isolation transformer is a type of transformer used to transfer electrical power from a source of alternating current (AC) power to a device or system while isolating the powered device from the power source, usually for safety reasons. It provides galvanic isolation which means there is no direct electrical connection between its primary and secondary windings, only magnetic coupling.

Working Principle: The isolation transformer operates on the principle of electromagnetic induction. When alternating current flows through the primary winding, it creates a varying magnetic field. This magnetic field induces an alternating voltage in the secondary winding, which is electromagnetically coupled to the primary winding. The induced voltage in the secondary winding is then used to power the load.

Transformation Ratio (K): The transformation ratio (K) of a transformer is defined as the ratio of the number of turns in the primary winding (N_p) to the number of turns in the secondary winding (N_s). Mathematically, it is expressed as:

K = N_p / N_s

In an isolation transformer, the primary and secondary windings have the same number of turns. Hence, the transformation ratio (K) is:

K = 1

This means that the voltage in the primary winding is equal to the voltage in the secondary winding, and the transformer provides no voltage step-up or step-down. It is primarily used for electrical isolation rather than voltage transformation.

Advantages:

• Provides electrical isolation between the power source and the load, enhancing safety.
• Reduces noise and interference in sensitive electronic equipment by isolating them from the power line noise.
• Protects against electric shocks and suppresses electrical surges.

Disadvantages:

• Does not provide voltage transformation (step-up or step-down) since the primary and secondary voltages are equal.
• May be bulkier and more expensive compared to non-isolating transformers with the same power rating.

Applications: Isolation transformers are widely used in medical equipment, sensitive electronic devices, industrial control systems, and any application where electrical isolation is critical for safety and noise reduction.

Correct Option Analysis:

The correct option is:

Option 2: K = 1

This option correctly describes the transformation ratio of an isolation transformer. Since the primary and secondary windings have an equal number of turns, the transformation ratio (K) is 1, meaning the voltage remains the same on both sides of the transformer.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: K > 1

This option suggests that the number of turns in the primary winding is greater than the number of turns in the secondary winding. This would imply a step-down transformer, where the secondary voltage is lower than the primary voltage. However, this is not characteristic of an isolation transformer, where the primary and secondary voltages are equal.

Option 3: K < 1

This option suggests that the number of turns in the primary winding is less than the number of turns in the secondary winding. This would imply a step-up transformer, where the secondary voltage is higher than the primary voltage. Again, this is not characteristic of an isolation transformer.

Option 4: K = 0

This option is incorrect as it is not possible for the transformation ratio (K) to be zero. A zero transformation ratio would imply no turns in the primary or secondary winding, which is not feasible for a functional transformer.

Conclusion:

Understanding the characteristics and operational principles of isolation transformers is essential for correctly identifying their transformation ratio. An isolation transformer, as explained, has a transformation ratio (K) of 1, meaning the primary and secondary voltages are equal. This unique feature makes isolation transformers suitable for applications requiring electrical isolation, noise reduction, and safety.