{"id":1662,"date":"2014-12-10T13:43:16","date_gmt":"2014-12-10T13:43:16","guid":{"rendered":"http:\/\/41j.com\/blog\/?p=1662"},"modified":"2014-12-10T13:43:16","modified_gmt":"2014-12-10T13:43:16","slug":"phase-shift-oscillator-high-pass-configuration","status":"publish","type":"post","link":"https:\/\/41j.com\/blog\/2014\/12\/phase-shift-oscillator-high-pass-configuration\/","title":{"rendered":"Phase Shift Oscillator &#8211; High Pass configuration"},"content":{"rendered":"<p><a href=\"http:\/\/41j.com\/blog\/2014\/12\/phase-shift-oscillator\/\">Yesterday<\/a> I took a look at a phase shift oscillator. The design I showed used a capacitor in a low pass configuration. I explained why this caused a phase shift allowing us to construct an oscillator.<\/p>\n<p>Today, I tried using the capacitors in a high pass configuration. To understand how this circuit works, we again need to understand how a capacitor in series will cause a voltage phase shift.<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_high.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_high-1024x322.png\" alt=\"phaseshift_high\" width=\"700\" height=\"220\" class=\"aligncenter size-large wp-image-1665\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_high-1024x322.png 1024w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_high-300x94.png 300w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><\/a><\/p>\n<p>The diagram above shows the configuration used, and it&#8217;s surprisingly similar to that shown <a href=\"http:\/\/41j.com\/blog\/2014\/12\/phase-shift-oscillator\/\">yesterday<\/a>. However this time when a voltage build up on the top of our capacitor the capacitor will need to draw current though the lower resistor to equalize the voltage. This will take time, causing a delay, and therefore a phase-shift as before. As before the phase-shift is limited to 90degrees (and a larger shift causes more attenuation). The circuit below uses 3 such circuits to generate a 180degree phase-shift:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_sch2.png\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_sch2.png\" alt=\"phaseshift_sch2\" width=\"523\" height=\"452\" class=\"aligncenter size-full wp-image-1663\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_sch2.png 523w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_sch2-300x259.png 300w\" sizes=\"auto, (max-width: 523px) 100vw, 523px\" \/><\/a><\/p>\n<p>I built the above circuit using a 2N2222 (a 2N3904 works as well). I used 22nF capacitors. Unlike the <a href=\"http:\/\/41j.com\/blog\/2014\/12\/phase-shift-oscillator\">previous example<\/a> these can&#8217;t be electrolytic. The resistors on the caps were 2.7K. The resistor going from the supply to the emitter was 12k and from the base to the supply 600k.<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_highpass-e1418217999666.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_highpass-e1418217999666-1024x768.jpg\" alt=\"phaseshift_highpass\" width=\"700\" height=\"525\" class=\"aligncenter size-large wp-image-1664\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_highpass-e1418217999666-1024x768.jpg 1024w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_highpass-e1418217999666-300x225.jpg 300w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_highpass-e1418217999666.jpg 1632w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><\/a><\/p>\n<p>And here&#8217;s the output:<\/p>\n<p><a href=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_h_trace.jpg\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_h_trace.jpg\" alt=\"phaseshift_h_trace\" width=\"800\" height=\"547\" class=\"aligncenter size-full wp-image-1666\" srcset=\"https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_h_trace.jpg 800w, https:\/\/41j.com\/blog\/wp-content\/uploads\/2014\/12\/phaseshift_h_trace-300x205.jpg 300w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Yesterday I took a look at a phase shift oscillator. The design I showed used a capacitor in a low pass configuration. I explained why this caused a phase shift allowing us to construct an oscillator. Today, I tried using the capacitors in a high pass configuration. To understand how this circuit works, we again [&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-1662","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1RRoU-qO","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1662","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=1662"}],"version-history":[{"count":1,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1662\/revisions"}],"predecessor-version":[{"id":1667,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/posts\/1662\/revisions\/1667"}],"wp:attachment":[{"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/media?parent=1662"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/categories?post=1662"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/41j.com\/blog\/wp-json\/wp\/v2\/tags?post=1662"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}