---------- From: owner-pcadusers To: technet Cc: pcadusers Subject: DES:ISOLATION Date: Thursday, May 30, 1996 9:32AM I'm not sure if this is the best place to ask electronics engineering type questions; so if anyone knows of an engineering-related forum, please let me know... I am in the process of designing a power board to military specs, and one of the requirements is "2500V isolation between primary and secondary". Using the formula that says 0.12 mils/volt, I am looking at a 300mil clearance wherever appropriate, right? One of the components in the design is an opto-isolator in a DIP8 package, and the data sheet guarantees 3000V insulation between primary and secondary. Since it is packaged in a DIP, and I am required to use 65 mil pads, I am only left with 235 mils between primary and secondary, which works out to (235/0.12) 1958.3 volts. Am I misinterpreting the requirements? <cut> I would definitely check the charts again. I just completed laying out a board that had 3500v isolation. I only needed 200 mils clearance. PCB and engineer are doing just fine. Note: the characteristics of the circuit may have been different though. Scott also at [log in to unmask]