{"id":2776,"date":"2012-05-14T15:07:29","date_gmt":"2012-05-14T22:07:29","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=2776"},"modified":"2012-08-14T05:27:16","modified_gmt":"2012-08-14T12:27:16","slug":"2012-05-14","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=2776","title":{"rendered":"2012-05-14 Watson&#8217;s Early Joule Thief Experiments"},"content":{"rendered":"<p><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=3664\" rel=\"attachment wp-att-3664\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-3664\" title=\"LEDVboost1953s\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/LEDVboost1953s-300x225.jpg\" alt=\"\" width=\"300\" height=\"225\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/LEDVboost1953s-300x225.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/LEDVboost1953s.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><a href=\"http:\/\/rustybolt.info\/wordpress\/?attachment_id=3648\" rel=\"attachment wp-att-3648\"><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-medium wp-image-3648\" title=\"Ledvboo1\" src=\"http:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/Ledvboo1-300x192.jpg\" alt=\"\" width=\"300\" height=\"192\" srcset=\"https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/Ledvboo1-300x192.jpg 300w, https:\/\/rustybolt.info\/wordpress\/wp-content\/uploads\/2012\/05\/Ledvboo1.jpg 740w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>I started experimenting with the LED V boost circuit, which later became popularly known as the Joule Thief.\u00a0 This pic, dated Sept 2001, is a not so good example.\u00a0 I used 36 AWG wire, which is too thin and has too high resistance; that&#8217;s why it was drawing only 19 mA current from the battery &#8211; it should be 70 to 80 mA.\u00a0 I made a mistake in the schematic &#8211; it shows a 10k resistor, which should be 1k.<\/p>\n<p>The ferrite core had lots of turns of wire, but because it was very low permeability, the frequency was very high, 190kHz.\u00a0 A typical JT today would have 25 turns max and a frequency of less than 100kHz.\u00a0 I doesn&#8217;t have to be a toroid, though, but a toroid is convenient.<\/p>\n<p>A few days later I changed the coil to a low permeability toroid, but again I used a lot of turns of too small wire.\u00a0 I hot glued the circuit to a piece of thin plywood so I could keep the coil wires from being pulled loose.<\/p>\n<p>Posted Aug 14, 2012.\u00a0 Back to experimenting&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I started experimenting with the LED V boost circuit, which later became popularly known as the Joule Thief.\u00a0 This pic, dated Sept 2001, is a not so good example.\u00a0 I used 36 AWG wire, which is too thin and has too high resistance; that&#8217;s why it was drawing only 19 mA current from the battery<a href=\"https:\/\/rustybolt.info\/wordpress\/?p=2776\"> <\/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-2776","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\/2776","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=2776"}],"version-history":[{"count":11,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2776\/revisions"}],"predecessor-version":[{"id":3643,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2776\/revisions\/3643"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2776"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2776"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2776"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}