An earlier blog about very lowpower Joule Thiefs is here.<\/p>\n
I experimented with a very low power Joule Thief using a SS9014 high gain, low noise NPN transistor, a red high brightness LED, a T231212T toroid with two 12 inch (300mm) lengths of 30 AWG (.25mm) solid enameled wire, and a 1k resistor in series with a 100k pot – the 1k was there to prevent the resistance going to zero, which would put the battery directly across the base to emitter and causing damage.\u00a0 I put a 68 pF disk capacitor in parallel with the pot; without it the circuit wouldn’t oscillate.<\/p>\n
With the pot set at minimum, the red LED was very bright; with the pot set at maximum, the LED was still bright.\u00a0 The battery current was still too high, more than 8 milliamps.\u00a0 This indicated that the S9014 was indeed very high gain – 600 or more.\u00a0 It also indicated that the 100k was too low, so I proceeded to increase it.\u00a0 I removed the 100k pot and soldered in a 470k pot.<\/p>\n
I powered it up, and the battery current was a lot lower, but still more than what I wanted it to be, which was about a half milliamp or less.\u00a0 So I knew my job would be to get an even higher resistor and put it in.\u00a0 I removed the 470k pot and soldered in a 1 meg resistor.\u00a0 Now I was getting down below the half milliamp point.\u00a0 The battery current measured about 375 microamps, or about 3\/8 of a milliamp.\u00a0 The red LED wasn’t very bright, but it was clearly visible.<\/p>\n","protected":false},"excerpt":{"rendered":"
An earlier blog about very lowpower Joule Thiefs is here. I experimented with a very low power Joule Thief using a SS9014 high gain, low noise NPN transistor, a red high brightness LED, a T231212T toroid with two 12 inch (300mm) lengths of 30 AWG (.25mm) solid enameled wire, and a 1k resistor in series <\/p>\n (Read More…)<\/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-7773","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\/7773","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=7773"}],"version-history":[{"count":10,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/7773\/revisions"}],"predecessor-version":[{"id":8241,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/7773\/revisions\/8241"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7773"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7773"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7773"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}