{"id":2748,"date":"2012-05-12T09:26:14","date_gmt":"2012-05-12T16:26:14","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=2748"},"modified":"2012-05-20T19:16:26","modified_gmt":"2012-05-21T02:16:26","slug":"2012-05-12","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=2748","title":{"rendered":"2012-05-12 Power Supply Self Destructs"},"content":{"rendered":"<p>This <a href=\"http:\/\/www.zen22142.zen.co.uk\/Circuits\/Power\/vpsu.htm\">power supply circuit<\/a> uses a LM317 or 7805 regulator chip to do the work.\u00a0 The problem is that when the wiper arm of R1 is turned to the position closest to the top, it will short the output to the common or adjust pin.\u00a0 This will cause the R1 pot to overheat and burn out and possibly damage the regulator and\/or other parts in the circuit.\u00a0 This is not a good thing to do.\u00a0 The solution is to put a resistor between the top end of R1 and the output pin so that the total resistance cannot be less than a certain amount.\u00a0 R1 is 10k so a resistor of 470 ohms seems to be a good choice to start at.\u00a0 It will reduce the voltage adjustment slightly, but that&#8217;s better than burning up, now, isn&#8217;t it?<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This power supply circuit uses a LM317 or 7805 regulator chip to do the work.\u00a0 The problem is that when the wiper arm of R1 is turned to the position closest to the top, it will short the output to the common or adjust pin.\u00a0 This will cause the R1 pot to overheat and burn<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=2748\"> <\/p>\n<p> (Read More&#8230;)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,17,25],"tags":[],"class_list":["post-2748","post","type-post","status-publish","format-standard","hentry","category-electronics","category-meters-and-test-equipment","category-power-supplies"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2748","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2748"}],"version-history":[{"count":8,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2748\/revisions"}],"predecessor-version":[{"id":2750,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2748\/revisions\/2750"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2748"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2748"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2748"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}