What component is responsible for converting high-voltage AC to low-voltage AC in an alarm system?

The transformer is the component that plays a crucial role in converting high-voltage alternating current (AC) to low-voltage AC in an alarm system. This is essential for the safe and efficient operation of alarm systems, which often require lower voltage levels to function without risking damage to sensitive components or wiring.

Transformers work based on the principle of electromagnetic induction, allowing the transfer of electrical energy between two or more circuits through inductively coupled conductors, known as coils or windings. By adjusting the turns ratio between the primary and secondary windings, it can either step down or step up the voltage as required.

The other components mentioned are not suited for this specific function: capacitors typically store and release electrical energy but do not convert voltages; resistors are used to limit current flow and manage voltage levels but do not change AC voltages; routers are networking devices limited to data transfer and do not deal with AC voltage conversion. Therefore, the transformer is the correct and essential component in this context.