How does a current transformer (CT) typically produce its rated output?

A current transformer (CT) is designed to produce a secondary current that is proportional to the current flowing in its primary circuit. The operation of a CT is fundamentally based on the principle of electromagnetic induction. When alternating current (AC) flows through the primary winding of the transformer, it generates a magnetic field. This magnetic field induces a current in the secondary winding, and the ratio of these currents is determined by the turns ratio of the transformer.

The rated output of a CT, therefore, is directly correlated to the amount of current in the primary circuit. This means that the CT’s output is a direct reflection of what is happening in the primary circuit, making it a reliable means of measuring or monitoring current. By sizing the current transformer appropriately for the expected range of primary current, the CT can ensure accurate and safe performance in power monitoring and protection systems.

The other options aren't aligned with how CTs function; for instance, being directly connected to the power source does not correctly represent their operational principle, and options involving capacitors or voltage adjustments do not fit with the fundamental design and purpose of current transformers.