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About ripple and noise
AC/DC Power Adapters — Desktop & Wall-Mount, this is a feature page about ripple and noise in switching power supplies. It provides basic knowledge about ripple and noise, and explains their relationship with the AC/DC Power Adapters — Desktop & Wall-Mount. If you have any questions, please feel free to .
“Ripple” and “Noise” are items that indicate the performance of an AC adapter, and they are listed in our specifications as follows (excerpt from the product specifications of Unifive).
| Item | Specification | Minimum | Typical | Maximum |
|---|---|---|---|---|
| Output Voltage | 24V | |||
| Output Voltage Range | Typical output voltage | 22.8V | 25.2V | |
| Load Current | 1A | |||
| Ripple | Input voltage (typ), full load current at 25℃ | 150mV | ||
| Noise | Input voltage (typ), full load current at 25℃ | 150mV | ||
| Hold-up Time | Input voltage (typ) and full load at 50Hz | 10mS | ||
| Startup Wait Time | 2S |
Both “Ripple” and “Noise” refer to slight fluctuations contained in the DC output voltage. Ideally, these should be zero, but due to technical reasons, it is difficult to eliminate them completely. The smaller these fluctuations, the better the performance of the AC adapter.
However, having smaller values does not automatically mean it is a “better AC adapter.” Reducing ripple and noise impacts the number and size of components used, which can make the adapter larger, heavier, and more expensive.
Therefore, it is necessary to define appropriate performance levels suitable for the devices being used and select the AC adapter accordingly.
Now, to explain the difference between “Ripple” and “Noise,” according to the standards set by the Japan Electronics and Information Technology Industries Association (JEITA), the following chart provides definitions.
(Excerpt from JEITA standards)
“Ripple” refers to fluctuations composed of frequency components of 50/60Hz from the AC power source, while “Noise” refers to fluctuations composed of high frequency components (tens of kHz or more) generated by the switching of the AC adapter. The combined total is called “Ripple Noise,” and the relationship is as follows: Ripple, Noise < Ripple Noise < Ripple + Noise.
Our company offers a variety of AC adapters tailored to different applications. Individual specifications can also be downloaded, so please take a look. We also specialize in custom options. If you have any questions, feel free to contact us. We are here to help fulfill your "if only there was something like this..." ideas.
Product catalogs are available for download in PDF format.
The JEITA standard introduced here can be purchased from the following page. Some can be viewed for free, so please check the site for more information.