What is the purpose of a current transformer?

A current transformer is specifically designed to measure alternating current (AC). It operates by utilizing electromagnetic induction, which allows it to produce a secondary current that is proportional to the primary current flowing through the conductor being measured. This capability is crucial for monitoring and controlling electrical systems safely and accurately.

In practical applications, a current transformer can provide a low current output that can be easily measured by standard instrumentation. This means that instead of dealing with high currents directly, engineers can work with manageable levels, leading to safer measurements without interrupting the circuit.

The other options address different functions. For example, increasing high voltage or converting low voltage to higher voltage involves transformers that operate differently. Converting alternating current into direct current pertains to rectification, which involves a different set of components and principles altogether. Thus, focusing on the measurement of AC through electromagnetic induction highlights the fundamental role of current transformers in electrical systems.