Which of the following are the main types of cores used in transformers?

The main types of cores used in transformers are typically the hollow core and shell core configurations. The hollow core consists of a central air gap, which can reduce losses and is often used in applications where a lighter core is advantageous. This design can be particularly useful for high-frequency transformers. On the other hand, the shell core design is favored for its efficient magnetic path and is more common in power transformers. It typically has a closed-loop design, which minimizes leakage flux and enhances the overall efficiency of the transformer.

Understanding the specific applications and advantages of these core types is crucial for anyone working with transformers, as they can significantly influence the performance characteristics, such as efficiency, size, and weight.