In the context of electrical circuits, what is the main purpose of a transformer?

The main purpose of a transformer is to increase or decrease voltage levels. This is accomplished through electromagnetic induction, where an alternating current in one coil of wire creates a magnetic field that induces a voltage in another coil. This allows transformers to step up voltage for efficient transmission over long distances or step down voltage for safe usage in homes and businesses.

Transformers are fundamental in electrical distribution systems, ensuring that power can be transmitted efficiently without significant losses, and then adjusted to appropriate voltage levels for end-users. The step-up function in power transmission reduces current, which minimizes losses associated with resistance in wires, while the step-down function allows for the use of that power in everyday appliances by adjusting the voltage to usable levels.

The other options do not align with the primary function of a transformer; for example, converting DC into AC involves inverter technology, while insulators are materials that prevent electrical current from flowing, and measurement of electrical currents is the function of instruments like ammeters rather than transformers.