Which type of transformer is typically connected in series?

A current transformer is primarily designed for measuring the current flow in a circuit. It operates on the principle of electromagnetic induction, converting high current levels into a lower, manageable value that can be safely measured by standard meters or monitoring equipment. This type of transformer is particularly effective for protection and monitoring in electrical power systems, and it is usually connected in series with the load to measure the current flowing through that load accurately.

When a current transformer is connected in series, it allows the transformer to accurately reflect the primary current in its secondary winding proportional to the turns ratio. This functionality is crucial for applications requiring precise current measurements and for protecting equipment by facilitating overload detection and safety monitoring in electrical installations.

In contrast, other types of transformers, such as step-down transformers or isolation transformers, are typically used for voltage conversion and are more often connected in parallel with the load. An auto-transformer, while capable of step-down voltage applications as well, does not specifically serve the same purpose as a current transformer and is less utilized for current measurement purposes.