{"id":1696,"date":"2014-12-13T00:19:35","date_gmt":"2014-12-13T00:19:35","guid":{"rendered":"http:\/\/41j.com\/blog\/?p=1696"},"modified":"2014-12-13T01:12:12","modified_gmt":"2014-12-13T01:12:12","slug":"tank-circuits","status":"publish","type":"post","link":"https:\/\/41j.com\/blog\/2014\/12\/tank-circuits\/","title":{"rendered":"Tank Circuits"},"content":{"rendered":"<p>In preparation for learning more about the Colpitts Oscillator, I wanted to understand Tank circuits a bit better. A Simple Tank (or LC) circuit is simple a Inductor and a capacitor in parallel:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/300px-LC_parallel_simple.svg.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/300px-LC_parallel_simple.svg.png\" alt=\"300px-LC_parallel_simple.svg\" width=\"300\" height=\"220\" class=\"aligncenter size-full wp-image-1700\" \/><\/a><\/p>\n<p>The tank circuit is useful because it results in a resonance. If you charge the capacitor and then remove power, the capacitor will discharge through the inductor. As the charge passes through the inductor it will build up a magnetic field, storing the energy. When the capacitor finishes discharging the field will collapse. This will result in a current, which will charge the other side of the capacitor, beginning the process again. The process will continue producing a frequency determined by the discharge rate of the capacitor and inductor. This frequency is given by the equation:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/freq.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/freq.png\" alt=\"freq\" width=\"94\" height=\"47\" class=\"aligncenter size-full wp-image-1701\" \/><\/a><\/p>\n<p>Wikipedia has a great animation of the process, replicated here (and slowed down slightly):<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank_slow.gif\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank_slow.gif\" alt=\"tank_slow\" width=\"400\" height=\"328\" class=\"aligncenter size-full wp-image-1699\" \/><\/a><\/p>\n<p>In a perfect world the resonance would keep going for ever, however losses due to the inductor resistance among other things means the resonance doesn&#8217;t last very long. You can see it on a scope however. To show this I connected a capacitor and inductor (22nF and 10uH) in parallel. The polarity will be reversing, so it&#8217;s likely unwise to use an electrolytic:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank-1024x720.jpg\" alt=\"tank\" width=\"700\" height=\"492\" class=\"aligncenter size-large wp-image-1697\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank-1024x720.jpg 1024w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank-300x210.jpg 300w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/tank.jpg 1280w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><\/a><\/p>\n<p>I then connected the power and set my scope to take a single shot, then removed the power. The result was the following trace:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/A6.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/A6.jpg\" alt=\"A6\" width=\"800\" height=\"547\" class=\"aligncenter size-full wp-image-1698\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/A6.jpg 800w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/A6-300x205.jpg 300w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><\/p>\n<p>Which as predicted by the equation above is ~340Khz.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In preparation for learning more about the Colpitts Oscillator, I wanted to understand Tank circuits a bit better. A Simple Tank (or LC) circuit is simple a Inductor and a capacitor in parallel: The tank circuit is useful because it results in a resonance. If you charge the capacitor and then remove power, the capacitor [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1],"tags":[],"class_list":["post-1696","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1RRoU-rm","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1696","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/comments?post=1696"}],"version-history":[{"count":3,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1696\/revisions"}],"predecessor-version":[{"id":1705,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1696\/revisions\/1705"}],"wp:attachment":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/media?parent=1696"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/categories?post=1696"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/tags?post=1696"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}