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Caroline Joy Barnhart
Your Kit must’ve had those “high quality” Radio Scrap components. 😆
My guess is you got one of the ITT2222 transistors. They made their plastic packaged version of the 2N2222 so that it did *not* conform to the standard E B C of the PN2222 or MPS2222. They were unpopular because they did not conform so Radio Shack’s ” 15 Assorted NPN” (or something named like that) package of transistors often had such oddball parts in them. I built a headphone amp and used these ITT2222 transistors connected up incorrectly, and they worked for more than a year before I found my mistake. Once I replaced them with the correct PN2222 transistors the headphone amplifier became louder and more sensitive. I stopped using those assorted parts packs from Radio Scrap.<\/p>\n\n\n\n
So you connected it up with the emitter and collector swapped. With the voltage well above 5V max – like a 9V battery – the emitter to base junction goes into avalanche mode and the transistor turns into a relaxation oscillator. All you need is the capacitor in parallel to charge up and discharge at audio frequencies just like a neon light bulb. 🤷<\/p>\n","protected":false},"excerpt":{"rendered":"
Caroline Joy Barnhart Your Kit must’ve had those “high quality” Radio Scrap components. 😆 My guess is you got one of the ITT2222 transistors. They made their plastic packaged version of the 2N2222 so that it did *not* conform to the standard E B C of the PN2222 or MPS2222. They were unpopular because they <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[338,255,293,74,2282,80],"tags":[2283,2287,2284,2285,2286,2288],"class_list":["post-18512","post","type-post","status-publish","format-standard","hentry","category-building-projects-and-kits","category-consumer-information","category-do-it-yourself","category-electronic-components","category-retail-sales","category-transistors","tag-assorted","tag-itt2222","tag-nonstandard","tag-pinout","tag-pn2222","tag-radio-scrap"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/18512","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=18512"}],"version-history":[{"count":1,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/18512\/revisions"}],"predecessor-version":[{"id":18513,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/18512\/revisions\/18513"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=18512"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=18512"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=18512"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}