> 2) I have seen mention of dipping a PCB in molten paraffin as a conformal > coat. Can anyone say if that is hermetic enough to remove the "typically >100 > ppm" drift from relative humidity changes
Such coating may give you a gain over the 1,000 hours you question, but it may be a detriment for longer time frames. As Conformal Coating is not a hermetic seal, what real happens is the impurities in the water are kept away from the circuit, but the water itself reaches the traces. Since the water is now fairly devoid of contaminates the water acts more like a dielectric insulator. You never notice it in a low impedance digital circuit, but unless debugging is an obsession don't let it get near a RF tuning circuit, a high impedance Wireless Sensor Network circuit, or a reference setting voltage divider. -- http://blog.softwaresafety.net/ http://www.designer-iii.com/ http://www.wearablesmartsensors.com/ _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
