{"id":6540,"date":"2013-03-07T08:00:15","date_gmt":"2013-03-07T16:00:15","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=6540"},"modified":"2013-03-09T04:28:43","modified_gmt":"2013-03-09T12:28:43","slug":"2013-03-07-tbd","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=6540","title":{"rendered":"2013-03-07 Low Current Supercharged Joule Thief"},"content":{"rendered":"<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=6574\" rel=\"attachment wp-att-6574\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-6574\" title=\"DSC_0145S3\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/DSC_0145S3-300x225.jpg\" alt=\"\" width=\"300\" height=\"225\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/DSC_0145S3-300x225.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2013\/03\/DSC_0145S3.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>I told Paul about my Supercharged Joule Thief but he had doubts about it having lower current consumption than a conventional Joule Thief.\u00a0 Originally I had set the value of the resistor to give the optimum current through the LED, and it was about 1.5k, which was good for about 20 mA LED current.\u00a0 But I had not tried to go lower than that when I experimented with the circuit.\u00a0 I decided to try changing the value of the resistor to a higher value to see if the circuit was still better than the conventional JT.<\/p>\n<p>I used my Supercharged JT Flasher board but with the flasher parts replaced with a jumper (see attached photo).\u00a0 This turned the circuit into a Supercharged JT.\u00a0 I put a 10k pot in series with the resistor but left everything else alone.\u00a0 The diode was a standard 1N4148 and the original resistor was 1k.\u00a0 The LED was a white one.\u00a0 The capacitor was a 1000 pF ceramic disk.\u00a0 The transistor was a TN3019A, a plastic equivalent of 2N3019A.\u00a0 It&#8217;s similar to the 2N2222A but higher power.\u00a0 I put a 1 ohm resistor in series with the cathode of the LED to allow me to measure the LED current.<\/p>\n<p>I applied 1.5V, and I adjusted the supply current for 25 milliamps.\u00a0 When I measured the LED current I got 9.4 milliamps, which was about half of the optimum LED current I try to get to the LED.\u00a0 I removed power and measured the pot, and found that it was set at 2650 ohms.\u00a0 I removed the pot and soldered a 2.7k resistor in series with the existing resistor for a total resistance of 3700 ohms.\u00a0 I applied power and checked the supply current at 1.5V and it was still 25 mA.\u00a0 I measured\u00a0 the voltage across the 1 ohm resistor and it was 9.4 millivolts which was the same as 9.4 milliamps.<\/p>\n<p>&nbsp;<\/p>\n<p>Thus the efficiency is 3.3V x 0.0094A divided by 1.5V x 0.025A.\u00a0 My calculations showed that this was 82.72 percent efficient, which is a lot better than a conventional JT.\u00a0 I did not try to optimize the circuit for the lower current, but I think I could have tweaked it a bit to improve it somewhat.\u00a0 The Supercharged Joule Thief circuit is a solid performer, and better than the conventional Joule Thief (see my comparisons <a href=\"http:\/\/www.rustybolt.info\/wordpress\/?p=221\">here<\/a>).<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I told Paul about my Supercharged Joule Thief but he had doubts about it having lower current consumption than a conventional Joule Thief.\u00a0 Originally I had set the value of the resistor to give the optimum current through the LED, and it was about 1.5k, which was good for about 20 mA LED current.\u00a0 But<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=6540\"> <\/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-6540","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\/6540","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=6540"}],"version-history":[{"count":11,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6540\/revisions"}],"predecessor-version":[{"id":6581,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6540\/revisions\/6581"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}