{"id":9071,"date":"2007-11-11T19:59:00","date_gmt":"2007-11-12T00:59:00","guid":{"rendered":"https:\/\/nuxx.net\/blog\/2007\/11\/11\/fudge-ripple\/"},"modified":"2026-07-01T11:36:15","modified_gmt":"2026-07-01T15:36:15","slug":"fudge-ripple","status":"publish","type":"post","link":"https:\/\/nuxx.net\/blog\/2007\/11\/11\/fudge-ripple\/","title":{"rendered":"Fudge Ripple"},"content":{"rendered":"<p><a href=\"https:\/\/nuxx.net\/blog\/wp-content\/uploads\/2026\/06\/IMG_9847.jpg\"><img decoding=\"async\" src=\"https:\/\/nuxx.net\/blog\/wp-content\/uploads\/2026\/06\/IMG_9847.jpg\" height=519 width=640 border=0><\/a><\/p>\n<p>That&#8217;s the AC ripple from the power supply mentioned <a href=\"http:\/\/c0nsumer.livejournal.com\/1083170.html\">here<\/a>, when connected to a 10 ohm 10% 10W power resistor, sinking ~490mA. The scope is set at 10mV and 5uS per division, probe at 1x, AC mode. In that image it&#8217;s being fed about 36VDC. Cutting that in half using only half the power supply (about 18VDC or so) gives <a href=\"https:\/\/nuxx.net\/blog\/wp-content\/uploads\/2026\/06\/IMG_9843.jpg\">this waveform<\/a>, with marginally less noise.<\/p>\n<p>The way I see that, peak to peak noise is about 50mV, so just about 1%. I <em>think<\/em> RMS would actually be a good bit lower, but my scope won&#8217;t figure that out for me and I think it&#8217;d be a lot of work to do it by hand. So, I think this should be an okay design&#8230; This is also on a breadboard, and something well laid out actually with a groundplane and all should be even better.<\/p>\n<p>I might head downstairs and pull out the second filter (inductor + capacitor) and see how much more noise it adds, but I&#8217;m fairly certain that it&#8217;ll be quite substantial.<\/p>\n<p>One thing is for certain, I really could use a better scope. I&#8217;m very tempted to just buy a refurb, $547 <a href=\"http:\/\/www.tek.com\/site\/ps\/0,,3G-15314-INTRO_EN,00.html?p_model_flex=TDS1002&#038;p_region=US\/CANADA\">Tek 1002<\/a>. However, I think I&#8217;d really rather have one of the B models, which adds serial and USB ports for getting data (screenshots, etc) right out of the scope.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>That&#8217;s the AC ripple from the power supply mentioned here, when connected to a 10 ohm 10% 10W power resistor, sinking ~490mA. The scope is set at 10mV and 5uS per division, probe at 1x, AC mode. In that image it&#8217;s being fed about 36VDC. Cutting that in half using only half the power supply\u2026<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,34],"tags":[],"class_list":["post-9071","post","type-post","status-publish","format-standard","hentry","category-electronics","category-moved-from-livejournal"],"_links":{"self":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/9071","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/comments?post=9071"}],"version-history":[{"count":4,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/9071\/revisions"}],"predecessor-version":[{"id":24656,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/9071\/revisions\/24656"}],"wp:attachment":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/media?parent=9071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/categories?post=9071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/tags?post=9071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}