No epoxy is going to be a good enough heat conductor. Get a piece of alumin= um sheet and cut it to size. Then stick the regulator to it with some arcti= c alumina and let it cure. Once that has completely cured, bend the aluminu= m into a circular form that will fit tightly inside the plug. Be careful no= t to break the regulator or snap it free from the heatsink while bending. If that doesn't work, there are switchmode phone chargers out there with th= e cigarette lighter plug and everything. If you find the right one, there a= re 1 or 2 resistors that need to be changed to set it to 3.3V, that's it. Y= ou might have to cut the cord to add the right connector, but no further mo= difications are necessary. Goodwill has baskets full of the things for a do= llar or two each. Cheers, Robert > ---------------------------------------- >> Date: Tue, 4 Mar 2014 11:26:14 -0500 >> From: cdenk@windstream.net >> To: piclist@mit.edu >> Subject: [EE] Heat sinking a 3.3 VDC switching regulator >> >> The application is an auto power (cigarette lighter) power outlet plug >> containing a 3.3 VDC switching regulator to power a handheld GPS. The >> regulator is a: >> http://www.dimensionengineering.com/products/de-sw033 >> which fits nicely in the plug housing. Initial testing using a 12 VDC >> bench supply was good, but when powered from 13.7 volt car battery, >> overheat caused the thermal protection to drop things out until it could >> cool down. >> >> The regulator has a 78XX pin out and a nice little aluminum heat sink. >> My first thought is to fill the housing cavity (1" dia.) with an epoxy >> or silicone with a bond breaker to the aluminum heat sink. After cure >> use a heat sink compound where the bond breaker was for good heat >> transfer. For the filler I'm thinking JBweld, but open to suggestions. >> Something with a good heat conduction. Would need to be something >> readily available. I do have a thin epoxy that I could add a filler, and >> have fine ground milled glass filler for it. >> >> >> Any thoughts appreciated. :) >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist =20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .