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What are EMI and RFI filters

When using technology that relies on the use of radio frequencies, such as AM and FM radio, it is important that they are able to function without interruption or interference. Two major inhibitors of electronics using radio frequency are electromagnetic interference (EMI) and radio-frequency interference (RFI). These two types of disturbances are problematic as they can detract from the efficiency of a circuit, or even stop it altogether. These interferences are caused by many natural phenomena and man-made sources including cell networks, solar flares, ignition systems, and more. Because of EMIs and RFIs causing errors and loss of data, it is important to have a way of combating their effect on electronic devices.

RFI and EMI interferences can either be radiated or conducted. EMI and RFI filters are electronic devices that can be installed on power and signal lines to help mitigate and dampen interference through the rejection of disruptive frequencies. While filters may protect the device from conducted interference, they do little to prevent radiated interference. To solve this issue, filters can also be installed onto devices that radiate interference, thus limiting the amount that they emit. Metal casings for filters can also help protect a device from radiated interference.

When choosing a filter, there are a few common types that can be utilized depending on the need. With low pass filters, only lower frequency signals may pass through, and all higher frequencies are rejected. High pass filters provide the adverse effect, allowing high frequency signals and blocking lower ones. Band pass filters are a filter type in which a range of signals are allowed and others are impeded. Lastly, band stop filters are the final standard filter in which most frequencies are allowed to pass and certain ranges are blocked. Depending on the application and need, different filters may be used to protect devices so that they can optimally function.

At ASAP Semiconductor, we can help you find EMI filter parts and electronic power supplies you need, new or obsolete. For a quick and competitive quote, email us at sales@asapsemi.com or call us at +1 (714) 705-4780.


January 20, 2021

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