{"id":2498,"date":"2019-01-28T00:07:53","date_gmt":"2019-01-27T21:07:53","guid":{"rendered":"http:\/\/spektrum.fi\/spektraklet\/?p=2498"},"modified":"2019-01-29T13:49:06","modified_gmt":"2019-01-29T10:49:06","slug":"piezoelektricitet","status":"publish","type":"post","link":"http:\/\/spektrum.fi\/spektraklet\/piezoelektricitet\/","title":{"rendered":"En mystisk kronometrisk kristall"},"content":{"rendered":"\n<p>L\u00e4saren vet s\u00e4kert att de flesta tidtagaruren fungerar med hj\u00e4lp av en liten kvartskristall, men har du t\u00e4nkt p\u00e5 vad kristallen egentligen g\u00f6r i klockan?  <br><\/p>\n\n\n\n<p>Kvarts \u00e4r ett intressant mineral p\u00e5 flera s\u00e4tt, men det som g\u00f6r det ypperligt f\u00f6r kronometrik \u00e4r dess piezoelektriska egenskaper.  Piezoelektricitet \u00e4r ett fenomen d\u00e4r ett (fast) \u00e4mne sl\u00e4pper ut en elektrisk st\u00f6t under mekanisk tryck. Notera att denna fenomen fungerar ocks\u00e5 bakl\u00e4nges; om man uts\u00e4tter kristallen f\u00f6r en elektrisk laddning deformeras den.<\/p>\n\n\n\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" width=\"474\" height=\"267\" src=\"https:\/\/www.youtube.com\/embed\/LnlSSWv4qTQ?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p style=\"text-align:left\">Ovan \u00e4r en video som demonstrerar piezoelektriska fenomenet. Kristallen i videon kan m\u00f6jligtvis skapa en elektrisk potential p\u00e5 \u00f6ver 10000 V, beroende s\u00e5 klart p\u00e5 kraften den uts\u00e4tts f\u00f6r.<\/p>\n\n\n\n<p>S\u00e5 hur utnyttjas piezoelekticiteten i klockor? F\u00f6rst formar man kvartsen till en pytteliten st\u00e4mgaffel. St\u00e4mgafflar, som ni redan vet, resonerar med en best\u00e4md frekvens beroende p\u00e5 dess material och tjockhet. Resonansen \u00e4r l\u00e4tt att uppeh\u00e5lla med en simpel krets som amplifierar de elektriska signalerna och matar dem tillbaka till kvartsgaffeln. Efter detta beh\u00f6ver man bara r\u00e4kna antalet oscillationer. Efter en viss m\u00e4ngd oscillationer (vanligtvis 32768 st) har en sekund passerat.<\/p>\n\n\n\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" width=\"474\" height=\"267\" src=\"https:\/\/www.youtube.com\/embed\/1pM6uD8nePo?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<\/div><figcaption> Bonus video. F\u00f6r de som \u00e4r intresserade av praktiska grejor, och hur saker och ting fungerar l\u00f6nar det sig att f\u00f6lja kanalen <em>engineerguy <\/em>p\u00e5 YouTube. <\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>L\u00e4saren vet s\u00e4kert att de flesta tidtagaruren fungerar med hj\u00e4lp av en liten kvartskristall, men har du t\u00e4nkt p\u00e5 vad kristallen egentligen g\u00f6r i klockan? Kvarts \u00e4r ett intressant mineral p\u00e5 flera s\u00e4tt, men det som g\u00f6r det ypperligt f\u00f6r kronometrik \u00e4r dess piezoelektriska egenskaper. Piezoelektricitet \u00e4r ett fenomen d\u00e4r ett (fast) \u00e4mne sl\u00e4pper ut &hellip; <a href=\"http:\/\/spektrum.fi\/spektraklet\/piezoelektricitet\/\" class=\"more-link\">Forts\u00e4tt l\u00e4sa <span class=\"screen-reader-text\">En mystisk kronometrisk kristall<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[142,42],"tags":[56,140,141],"_links":{"self":[{"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/posts\/2498"}],"collection":[{"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/comments?post=2498"}],"version-history":[{"count":9,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/posts\/2498\/revisions"}],"predecessor-version":[{"id":2519,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/posts\/2498\/revisions\/2519"}],"wp:attachment":[{"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/media?parent=2498"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/categories?post=2498"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/spektrum.fi\/spektraklet\/wp-json\/wp\/v2\/tags?post=2498"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}