What is the primary purpose of a rectifier in a power supply?

The primary purpose of a rectifier in a power supply is to convert alternating current (AC) into direct current (DC). This conversion is essential because many electronic devices and circuits require a steady and unidirectional flow of current to operate correctly.

In detail, AC voltage alternates in polarity, oscillating between positive and negative values. A rectifier takes this AC input and allows current to flow only in one direction, effectively modifying the waveform of the input signal. There are various types of rectifiers, including half-wave and full-wave, which can affect how efficiently the conversion occurs, but the fundamental role remains the same: transforming AC into a usable DC form.

Other options pertain to functions that are relevant to power supplies but do not directly relate to the core purpose of a rectifier. For instance, reducing noise is more aligned with filtering components, whereas increasing voltage is typically managed by transformers or boost converters. Filtering signals is often accomplished with capacitors and inductors in conjunction with rectifiers to smooth out the resulting DC after conversion, but it is not the primary function of the rectifier itself.