What is the primary function of electrical transformers?

The primary function of electrical transformers is to change the voltage level in an alternating current (AC) system while maintaining the power within the circuit. Transformers operate on the principle of electromagnetic induction, enabling them to step up (increase) or step down (decrease) voltages as needed for efficient power transmission and distribution.

When a transformer increases voltage (step-up transformer), it decreases current, which is crucial for long-distance power transmission since higher voltage allows for lower current and reduced energy loss in the form of heat due to resistance in the wires. Conversely, a step-down transformer lowers the voltage but increases current for distribution to end users.

Since transformers fundamentally modify both voltage and current as per the conservation of energy, where power (measured in watts) is conserved, the correct answer recognizes that transformers have the capacity to influence both voltage and current in a circuit. Thus, choosing an answer that acknowledges the roles of both voltage and current accurately reflects the integral function of transformers in electrical systems.