What type of current can be stepped down through transformers to be at a safe level for residential housing?

Transformers are electrical devices that operate on the principle of electromagnetic induction, most commonly used with alternating current (AC). They are designed to increase or decrease voltage levels in AC circuits. In residential settings, the electrical system typically uses AC to distribute power from generating stations to homes.

The ability of transformers to step down voltage is crucial for ensuring that the electricity supplied to homes is at a safe level. For example, high voltage transmission lines carry electricity at voltages that can be extremely dangerous. Transformers reduce this voltage to a suitable level—usually 120V or 240V—making it safe for household use.

In contrast, direct current (DC) cannot be stepped down by transformers because it does not alternate direction; rather, it flows steadily in one direction. High voltage current refers to the high voltage levels used in transmission to minimize losses over distance but does not specify a type of current that can be transformed safely. Minimal current doesn't accurately describe a category of current relevant to this context; rather, the focus should be on the voltage characteristics and the type of current being transformed.

Thus, alternating current is the correct answer, as it is the type of electrical current that transformers are specifically used to step down for safe residential use.