{"id":624,"date":"2017-02-15T21:58:43","date_gmt":"2017-02-15T21:58:43","guid":{"rendered":"http:\/\/andrewburton.co.uk\/website\/?p=624"},"modified":"2017-02-15T22:26:04","modified_gmt":"2017-02-15T22:26:04","slug":"624-2","status":"publish","type":"post","link":"https:\/\/andrewburton.co.uk\/website\/624-2\/","title":{"rendered":"555 timer calculator"},"content":{"rendered":"<p><script type='text\/javascript' src='http:\/\/houseofjeff.com\/wp-content\/plugins\/youtube-embed-plus\/scripts\/ytprefs.min.js?ver=4.4.7'><\/script><\/p>\n<p><script type=\"text\/javascript\">\nvar _gaq = _gaq || [];\n_gaq.push(['_setAccount', 'UA-39089885-1']);\n_gaq.push(['_trackPageview']);\n(function() {\nvar ga = document.createElement('script'); ga.type = 'text\/javascript'; ga.async = true;\nga.src = ('https:' == document.location.protocol ? 'https:\/\/ssl' : 'http:\/\/www') + '.google-analytics.com\/ga.js';\nvar s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);\n})();\n<\/script><\/p>\n<div class=\"entry-content e-content\">\n<p><script type=\"text\/javascript\" src=\"http:\/\/www.andrewburton.co.uk\/scripts\/555.js\"><\/script><\/p>\n<div class=\"entry-content e-content\" itemprop=\"description text\">\n<p><script type=\"text\/javascript\" src=\"http:\/\/www.andrewburton.co.uk\/scripts\/555.js\"><\/script><\/p>\n<p><img decoding=\"async\" src=\"http:\/\/andrewburton.co.uk\/website\/wp-content\/uploads\/2017\/02\/555diagram.png\" alt=\"555diagram\" class=\"aligncenter\" \/><\/a><\/p>\n<p>Fill in one of the values below and press &#8216;go&#8217; and the calculator will give you a range of options for R<sub>1<\/sub>, R<sub>2<\/sub> &#038; C<sub>1<\/sub>.<\/p>\n<table cellspacing='5'>\n<tr>\n<td>How often do you want the timer to fire?<\/td>\n<td><input type='text' id='txtSeconds' style='Width:50px'><\/td>\n<td>seconds<\/td>\n<td><input type='button' onClick='calcSeconds();' value='Go'><\/td>\n<\/tr>\n<tr>\n<td>What frequency do you want the timer to fire at?<\/td>\n<td><input type='text' id='txtHertz' style='Width:50px'><\/td>\n<td>Hertz<\/td>\n<td><input type='button' onClick='calcHertz()' value='Go'><\/td>\n<\/tr>\n<\/table>\n<p \/>\n<div id='resultsdiv'><\/div>\n<div id='caveat' style=\"visibility:hidden;display:none;\">\nI have included the &#8216;duty cycle&#8217; of the configuration. This didn&#8217;t matter for my purposes &#8212; I just needed a rising signal on a regular interval &#8212; but you might find it useful.<\/p>\n<p>The values above are based on &#8216;perfect&#8217; resistors and capacitors.  Most common resistors can vary by up to 10% from the stated value, and capacitors by up to 20%.   If you find your results differ significantly from what you expect, you should test your components.  If possible, prefer a ceramic disc capacitor over an electrolytic (which can be &#8216;leaky&#8217;) and if precision is really important, look at ordering some resistors with 1% tolerance (and test them anyway!).<\/p>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Fill in one of the values below and press &#8216;go&#8217; and the calculator will give you a range of options for R1, R2 &#038; C1. How often do you want the timer to fire? seconds What frequency do you want the timer to fire at? Hertz I have included the &#8216;duty cycle&#8217; of the configuration. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42],"tags":[],"class_list":["post-624","post","type-post","status-publish","format-standard","hentry","category-electronics"],"_links":{"self":[{"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/posts\/624","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/comments?post=624"}],"version-history":[{"count":17,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/posts\/624\/revisions"}],"predecessor-version":[{"id":642,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/posts\/624\/revisions\/642"}],"wp:attachment":[{"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/media?parent=624"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/categories?post=624"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/andrewburton.co.uk\/website\/wp-json\/wp\/v2\/tags?post=624"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}