{"id":11349,"date":"2016-09-06T21:19:20","date_gmt":"2016-09-07T04:19:20","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=11349"},"modified":"2016-09-07T17:55:37","modified_gmt":"2016-09-08T00:55:37","slug":"2016-09-06-supercharged-jt-shutoff","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=11349","title":{"rendered":"2016-09-06 Supercharged JT Shutoff"},"content":{"rendered":"<p>I had a hard time editing the reply to #2 of the comment, besides it&#8217;s a good blog.  The following applies to my Supercharged Joule Thief.<\/p>\n<p><a href=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2016\/09\/wpid-wp-1473222129612.jpg\"><img decoding=\"async\" title=\"wp-1473222129612\" class=\"alignnone size-full\"  alt=\"image\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2016\/09\/wpid-wp-1473222129612.jpg\" \/><\/a> <\/p>\n<p>But you really don&#8217;t need to use a MOSFET.  Any PNP transistor, 2N3906 or BC557, will do the job, and the current will be relatively low.  Replace the diode with the transistor.  Put a 47k resistor from its base to negative, and the photocell from base to emitter.  The collector goes to the resistor.  See the schematic photo.<\/p>\n<p>I&#8217;ve never tried this circuit.  Right now, the PNP makes sense because it should act like a diode.  The PNP may have to be changed to NPN and flipped around and negative changed to the coil and collector as the diode, but that would seem to me like the NPN would then be reverse biased.<\/p>\n<p>Anyhow I would want to modify one of my SJTs to see if it works.  There may not be enough current to shut the NPN off, and what there is may cause the SJT circuit to not shut completely off.<\/p>\n<p>I&#8217;ll update when I experiment.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I had a hard time editing the reply to #2 of the comment, besides it&#8217;s a good blog. The following applies to my Supercharged Joule Thief. But you really don&#8217;t need to use a MOSFET. Any PNP transistor, 2N3906 or BC557, will do the job, and the current will be relatively low. Replace the diode<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=11349\"> <\/p>\n<p> (Read More&#8230;)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-11349","post","type-post","status-publish","format-standard","hentry","category-joule-thief-smps-dc-dc"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11349","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=11349"}],"version-history":[{"count":4,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11349\/revisions"}],"predecessor-version":[{"id":11354,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11349\/revisions\/11354"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}