Which devices are used to convert alternating current (AC) to direct current (DC)?

Rectifiers are the devices specifically designed to convert alternating current (AC) to direct current (DC). They perform this function by allowing current to flow only in one direction, effectively blocking the negative half-cycles of the AC waveform. This is achieved through the use of semiconductor materials, such as diodes, which are fundamental components in rectifier circuits.

When AC voltage is applied to a rectifier, the output is pulsed DC, which can be further smoothed into a more stable DC output using filters. The ability of rectifiers to convert AC to DC is crucial for powering electronic devices, which typically require a steady DC voltage for operation.

In contrast, transformers are used to change the voltage level in AC circuits but do not convert AC to DC. Capacitors and inductors also have functions related to AC circuits but do not serve the purpose of rectification. Capacitors can store and release electric charge and are often used in filtering applications, while inductors store energy in a magnetic field, both of which are important in AC systems but not in the direct conversion to DC.