Ripples are periodic voltage variations or fluctuations in the output of a power supply and are AC interference signals superimposed on the stable DC output. Measured in millivolts (mV), ripples are a component that is synchronous with the switching frequency. Ripple characteristics vary across different power supplies and can result from power supply design choices, power filter performance, load variations, or other external disturbances. Unlike ripples, noise is a high-frequency component appearing between output terminals as non-periodic random interference. Essentially, power supply noise comprises discontinuous, irregular voltage or current spikes caused by various internal or external disturbances to the system, such as suboptimal circuit design, improper wiring, and poor contact.