What is the main purpose of a capacitor in a rectifier circuit?

In a rectifier circuit, the main purpose of a capacitor is to filter the output voltage. After the rectification process, the output voltage typically contains ripples due to the alternating current being converted to direct current. The capacitor smooths out these voltage fluctuations by charging when the voltage increases and discharging when the voltage decreases. This action helps to create a more stable and constant output voltage, which is critical for the proper operation of most electronic devices and circuits that require a steady DC voltage.

The filtering done by the capacitor significantly reduces the ripple voltage, ensuring that the power supply provides a higher quality direct current. This is essential for improving the performance of the electronic components that will be powered by the rectifier circuit.