{"id":2110,"date":"2011-12-27T09:39:38","date_gmt":"2011-12-27T17:39:38","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=2110"},"modified":"2013-03-23T23:53:13","modified_gmt":"2013-03-24T06:53:13","slug":"2011-12-27-troubleshooting-joule-thief-problems","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=2110","title":{"rendered":"2011-12-27 Troubleshooting Joule Thief Problems"},"content":{"rendered":"<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=235\" rel=\"attachment wp-att-235\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-2114\" title=\"JT-pictorial\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2011\/12\/JT-pictorial-300x188.gif\" alt=\"\" width=\"300\" height=\"188\" \/><\/a>Some of the most common reasons why a JT doesn&#8217;t work are:<\/p>\n<p>The windings are incorrectly connected.\u00a0 You can usually fix this by disconnecting ONE winding and swapping the two wires.\u00a0 If you have a fresh battery connected to your non-working JT, measure the voltage at the collector of the transistor.\u00a0 It should be the same as the battery voltage.\u00a0 If not, you may have the winding wires even more messed up than that (especially if your wires are the same color).\u00a0 Check continuity with a DMM on ohms or continuity range.<\/p>\n<p>The transistor is getting too much bias current and won&#8217;t oscillate.\u00a0 If your JT does not work at 1.5V, but works at a lower battery voltage (try a depleted battery), then this could be the problem.\u00a0 Increase the 1000 ohm resistor to a higher value or else add another in series to make 2k ohms.<\/p>\n<p>Often the leads to the transistor are mistakenly reversed.\u00a0 The 2N4401, PN2222A, 2N3904 transistors pinouts are E B C looking at the bottom with the flat side up.\u00a0 The BC337, BC547 transistors are C B E.\u00a0 The Japanese 2SC1815, 2SC945 transistors are E C B.<\/p>\n<p>The 1k ohm resistor should have the colors BROWN, BLACK, RED, GOLD.\u00a0 If not, then you may have the wrong value resistor.\u00a0 The red band is especially important.<\/p>\n<p>The transistor is the wrong type (PNP instead of NPN), or defective.\u00a0 Sometimes the transistor shows no sign of damage even though it has been burned out.\u00a0 Use another transistor.\u00a0 Don&#8217;t forget that whatever caused the first one to be damaged might also cause the second (or third) one to also be damaged.\u00a0 It is a wise thing to make sure that there are no other errors before you damage more transistors.<\/p>\n<p>The LED is backwards.\u00a0 Make sure that the\u00a0 cathode (has a flat spot on the plastic next to the lead) is connected to the negative of the battery.<\/p>\n<p>I&#8217;ve included a pictorial (simplified drawing) of how a Joule Thief should look.\u00a0 I hope this helps the experimenter get an idea of what he may be doing wrong.<\/p>\n<p>Back to troubleshooting&#8230;\u00a0 \ud83d\ude09<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Some of the most common reasons why a JT doesn&#8217;t work are: The windings are incorrectly connected.\u00a0 You can usually fix this by disconnecting ONE winding and swapping the two wires.\u00a0 If you have a fresh battery connected to your non-working JT, measure the voltage at the collector of the transistor.\u00a0 It should be the<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=2110\"> <\/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":[4,17],"tags":[33,30,31,32],"class_list":["post-2110","post","type-post","status-publish","format-standard","hentry","category-joule-thief-smps-dc-dc","category-meters-and-test-equipment","tag-doesnt-work","tag-joule-thief","tag-problem","tag-troubleshoot"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2110","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=2110"}],"version-history":[{"count":17,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2110\/revisions"}],"predecessor-version":[{"id":2112,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2110\/revisions\/2112"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2110"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2110"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}