{"id":4421,"date":"2012-09-29T16:13:23","date_gmt":"2012-09-29T23:13:23","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=4421"},"modified":"2013-06-29T18:54:05","modified_gmt":"2013-06-30T01:54:05","slug":"2012-09-29-a-100-mv-or-110-volt-joule-thief","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=4421","title":{"rendered":"2012-09-29 A 100 mV or 1\/10 Volt Joule Thief"},"content":{"rendered":"<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=4428\" rel=\"attachment wp-att-4428\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-4428\" title=\"DSC_0219S2\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0219S2-300x216.jpg\" alt=\"\" width=\"300\" height=\"216\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0219S2-300x216.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0219S2.jpg 833w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>I made this JT with a transformer I pulled out of an old switch mode power supply from a PC (see the first photo).\u00a0 The upper coil had a single turn as it came from the PS, so I removed that and wound 15 turns of 26 AWG enameled wire on the bobbin.\u00a0 Its inductance was somewhat more than 100 uH, and the turns ratio of it and the other (bottom) winding was about 1 to 5.\u00a0 The upper winding became the primary (connected to the collector).\u00a0 The transistor was a BC337-40, and the resistor was a 220 ohm 1\/4 watt.\u00a0 The LED was a yellow superbright.<\/p>\n<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=4429\" rel=\"attachment wp-att-4429\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-4429\" title=\"DSC_0218S2\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0218S2-300x224.jpg\" alt=\"\" width=\"300\" height=\"224\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0218S2-300x224.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/09\/DSC_0218S2.jpg 514w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>The LED was connected anode to the collector and cathode (flat spot) connected to the base. This takes advantage of the greatest difference of potential when the transistor shuts off.<\/p>\n<p>The second photo shows the LED glowing with 100 millivolts or 1\/10 volt from the supply.\u00a0 The LED is still glowing, though weakly.\u00a0 The circuit starts at 0.408 volt, and will still keep running below 100 mV, but the LED will be very dim.\u00a0 The frequency was 3 kHz.<\/p>\n<p>The supply current at 1\/4 volt was 46 mA, and at 1\/2 volt was 96 mA.\u00a0 I think this circuit would make a good converter for a single solar cell that puts out 1\/2 volt.\u00a0 But the 220 ohm resistor will have to be adjusted to accommodate the current output of the particular cell that is being used.\u00a0 The idea is to have the circuit put the optimum load on the cell when it&#8217;s putting out at its best.<\/p>\n<p>Back to experimenting&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I made this JT with a transformer I pulled out of an old switch mode power supply from a PC (see the first photo).\u00a0 The upper coil had a single turn as it came from the PS, so I removed that and wound 15 turns of 26 AWG enameled wire on the bobbin.\u00a0 Its inductance<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=4421\"> <\/p>\n<p> (Read More&#8230;)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,34],"tags":[],"class_list":["post-4421","post","type-post","status-publish","format-standard","hentry","category-joule-thief-smps-dc-dc","category-renewable-energy"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4421","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=4421"}],"version-history":[{"count":9,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4421\/revisions"}],"predecessor-version":[{"id":4423,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/4421\/revisions\/4423"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4421"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4421"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}