Do you know what conformal coating is? It is a protective chemical, or you can say a polymer film between 25 - 75 µm thick. However, most of the conformal coatings found on the market, are of 50 µm thick. If you apply this coating on your PCB, then it will protect the PCB from the harsh environment, various pollutants, and chemical reactions. http://www.sooperarticles.com/shopping-articles/electronics-articles/benefits-buying-conformal-coating-pcb-1601055.html

Which Relay Is the Best for Your Need?
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How Not to Get Deceived When Choosing The Correct Electronic Components Store
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