Whats ripple voltage?

Ripple voltage is the small fluctuation or variation in the direct current (DC) output of a power supply or rectifier. It is caused by the imperfect filtering of the AC voltage waveform during the conversion process from AC to DC. The ripple voltage is typically expressed as a percentage of the DC voltage and is measured in millivolts (mV) or microvolts (µV). A lower ripple voltage indicates a smoother and more stable DC output.