What is ripple and noise?

This page is about ripple and noise of AC adapters or switching power supplies. It describes basic information on ripple and noise and their relationship with AC adapters. If you have any questions, please do not hesitate to contact us.

Ripple and noise are elements which indicate the performance of AC adapters and are written in our specifications as follows. (Extract from UNIFIVE Product Specification)

ItemSpecMinRepresentative valueMax
Output 24.0V
Output voltage range Typical Output voltage 22.8V 25.2V
Load current 1A
Ripple Input(typ)full load current 25℃ 150mV
Noise Input(typ)full load current 25℃ 150mV
Output retention time Input(typ),full load current 50Hz 10mS
Activation wait time 2S

Both ripple and noise are minute DC fluctuations contained in the output voltage, which is direct current and should theoretically be zero, but in principle it is difficult to completely eliminate it, small ripple noise is a key factor in the quality of an AC adapter.

Producing the least amount of ripple or noise is not synonymous with producing the best AC adapter, because in order to reduce the ripple or noise, the quantity and size of parts used will increase, and the product will become big, heavy, and more expensive.

Therefore, it is necessary to select optimum performance for the equipment you require in your AC adapter.

The difference between ripple and noise are explained in the standards stipulated in the figure shown below courtesy of the Japan Electronics and Information Technology Industries Association (JEITA).


Ripple is fluctuation consisting of a frequency of 50/60 Hz in AC power supply, and noise is fluctuation consisting of a frequency of several tens of kHz or more caused by the switching of an AC adapter. There is a relationship between the interaction between them and the combination of them.

 "ripple noise", "ripple", "noise" <"ripple noise" <"ripple" + "noise".

At our company, various AC adapters are prepared according to application, and individual specifications can also be downloaded. We can also deliver individualized correspondence, so if you have any questions, please do contact us.

You can get the product catalog in PDF.

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The JEITA standard introduced here can be purchased from the following page. There is also information available for free if you are only browsing, so please refer to their website for more details.

JEITA Standard,General Electronic Components Division,Conversion Parts Relationship

You can get the product catalog in PDF.

Product initiatives

Since 1989, UNIFIVE has maintained the quality of their AC power adapters and switching power supplies through rigorous quality controls.

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