{"id":6835,"date":"2013-03-24T22:55:37","date_gmt":"2013-03-25T05:55:37","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=6835"},"modified":"2013-03-26T10:00:25","modified_gmt":"2013-03-26T17:00:25","slug":"2013-03-24-tbd","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=6835","title":{"rendered":"2013-03-24  Two Transistor &#8220;JT&#8221; Uses Inductor From CFL"},"content":{"rendered":"<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=6846\" rel=\"attachment wp-att-6846\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-6846\" title=\"RSCN0885S4\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/RSCN0885S4-300x225.jpg\" alt=\"\" width=\"300\" height=\"225\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/RSCN0885S4-300x225.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/RSCN0885S4.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>I put this together during the Xmas holidays back in 2008.\u00a0 It may have been posted to my watsonseblog, I don&#8217;t remember.\u00a0 But here it is for the world to see again.<\/p>\n<p>It&#8217;s the typical 2 transistor voltage boost circuit &#8211; often mistakenly called a Joule Thief &#8211; with a BC337-25 for the driver transistor.\u00a0 I used the choke or inductor from a defective CFL light bulb.\u00a0 The two transistor circuit allows the use of a coil with a single winding.\u00a0 The DC resistance of this choke is high which reduces the output and decreases the efficiency, but it puts out some light, as can be seen in the photo.<\/p>\n<p>I see that the 100 pF &#8220;102&#8221; capacitor has a paralleled pair of 22k resistors (equal to 11k) in series.\u00a0 Recently I put a 10k or 25k trimpot in series and adjusted it and noticed that the LED gets brightest at some point of a very broad peak.\u00a0 Apparently this resistance makes the current pulse broader, and there&#8217;s a point where it&#8217;s at an optimum width.\u00a0 This resistance, the capacitor and the inductor influence the circuit parameters that determine the frequency of the circuit.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I put this together during the Xmas holidays back in 2008.\u00a0 It may have been posted to my watsonseblog, I don&#8217;t remember.\u00a0 But here it is for the world to see again. It&#8217;s the typical 2 transistor voltage boost circuit &#8211; often mistakenly called a Joule Thief &#8211; with a BC337-25 for the driver transistor.\u00a0<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=6835\"> <\/p>\n<p> (Read More&#8230;)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-6835","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\/6835","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=6835"}],"version-history":[{"count":13,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6835\/revisions"}],"predecessor-version":[{"id":6854,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6835\/revisions\/6854"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}