What is a common technique used to reduce core losses and the magnetising component in a current transformer? 

Option 1, "Utilizing laminated cores made of insulated sheets," is correct.

Explanation:

• This technique is commonly employed to reduce core losses and the magnetizing component in a current transformer.
• Laminated cores consist of thin insulated sheets, which minimize eddy current losses by restricting the path of circulating currents within the core.
• This design effectively reduces core heating and improves the transformer's efficiency.
• By using laminations, the magnetic flux experiences less resistance and, as a result, the transformer exhibits lower core losses.