{"id":272,"date":"2018-09-27T16:30:40","date_gmt":"2018-09-27T16:30:40","guid":{"rendered":"http:\/\/blogs.plymouth.ac.uk\/embedded-systems\/?page_id=272"},"modified":"2018-10-05T09:33:45","modified_gmt":"2018-10-05T09:33:45","slug":"topic-2-potential-dividers-problem-based-learning-task","status":"publish","type":"page","link":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/microcontrollers\/mbed-os-2\/courses\/embedded-systems-in-context-level-4\/topic-2-potential-dividers-problem-based-learning-task\/","title":{"rendered":"Topic 2 &#8211; Potential Dividers (Problem Based Learning task)"},"content":{"rendered":"<p><a href=\"http:\/\/blogs.plymouth.ac.uk\/embedded-systems\/mbed-os-2\/courses\/embedded-systems-in-context-level-4\/\">Back to ToC<\/a><\/p>\n<p>This is a task that requires you the learner to take responsibility for your learning.\u00a0You will be given a problem statement. In this problem statement are some highlighted key terms \/ jargon.<\/p>\n<ul>\n<li>It is your task to research these terms in order to understand the problem and to attempt to solve it.<\/li>\n<li>Start with the references provided.<\/li>\n<li>Don\u2019t feel bad if you struggle and feel free to work with others to try and tackle this problem.<\/li>\n<\/ul>\n<h2><b>Intended Learning Outcomes<\/b><\/h2>\n<ol>\n<li>Calculate the total resistance of two resistors in series<\/li>\n<li>Calculate the total resistance of two resistors in parallel<\/li>\n<li>Calculate the current through two resistors in series<\/li>\n<li>Derive the equation for potential division using two resistors<\/li>\n<li>Use a potential divider to create a voltage reference<\/li>\n<li>Calculate the Th\u00e9venin equivalent circuit of a potential divider voltage source.<\/li>\n<li>From (6), describe the trade offs between power consumption, noise and output resistance.<\/li>\n<\/ol>\n<h1>Problem Statement<\/h1>\n<p>Real world voltage sources can be modeled as an ideal voltage source V and an internal resistor, as shown below.\u00a0The power supply on the Nucleo Board is 3.3V, with a small internal resistance. For the purposes of this exercise, we will ignore this internal resistance and assume it to be close to ideal.<\/p>\n<h2><b>Problem A (everyone)<\/b><\/h2>\n<p>Using the Nucleo Board power supply and two resistors,<\/p>\n<ol>\n<li>design a <b>potential divider<\/b> circuit to create a <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-7cf7072ced21e65241d1d7a8631b720c_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#50;&#46;&#50;&#86;\" title=\"Rendered by QuickLaTeX.com\" height=\"12\" width=\"37\" style=\"vertical-align: 0px;\"\/>\u00a0<b>voltage reference<\/b> using two resistors. The <b>quiescent current<\/b> should be <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-7a3e6dd89503418b333e5d9a11fcc22b_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#92;&#108;&#101;&#113;&#32;&#49;&#109;&#65;\" title=\"Rendered by QuickLaTeX.com\" height=\"16\" width=\"56\" style=\"vertical-align: -3px;\"\/><\/li>\n<li>calculate the series resistance of the two resistors<\/li>\n<li>calculate the quiescent <b>power consumption<\/b> of your design (when not under load). Quote your answer in milliwatts (mw).<\/li>\n<\/ol>\n<h2><b>Problem B (advanced)<\/b><\/h2>\n<p><b><i>NOTE &#8211; Only attempt this if you are very confident and\/or have plenty of spare time!<\/i><\/b><\/p>\n<p>Derive the <b>Th\u00e9venin equivalent circuit<\/b> for the voltage source (see over) of this new 2.2V source.<\/p>\n<ul>\n<li>What is the internal resistance <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-72bf50ac79297b99e08471bee72a462c_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#82;&#95;&#123;&#105;&#110;&#116;&#125;\" title=\"Rendered by QuickLaTeX.com\" height=\"15\" width=\"31\" style=\"vertical-align: -3px;\"\/>?<\/li>\n<li>If this new voltage source were to drive a <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-12b31707897b77afe8ff703292c725e0_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#49;&#107;&#92;&#79;&#109;&#101;&#103;&#97;\" title=\"Rendered by QuickLaTeX.com\" height=\"12\" width=\"30\" style=\"vertical-align: 0px;\"\/>\u00a0load, what would be the output voltage Vout?<\/li>\n<li>If this new voltage source were to drive a <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-2285db0c8b5b48cc7e06550f0c44ddab_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#49;&#77;&#92;&#79;&#109;&#101;&#103;&#97;\" title=\"Rendered by QuickLaTeX.com\" height=\"12\" width=\"39\" style=\"vertical-align: 0px;\"\/>\u00a0load, what would be the output voltage <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-f6d243eef9c716d3b02cc6e463827a76_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#86;&#95;&#123;&#111;&#117;&#116;&#125;\" title=\"Rendered by QuickLaTeX.com\" height=\"15\" width=\"30\" style=\"vertical-align: -3px;\"\/>?<\/li>\n<li>What changes would you have to make to make this suitable for driving a <img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/ql-cache\/quicklatex.com-12b31707897b77afe8ff703292c725e0_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#49;&#107;&#92;&#79;&#109;&#101;&#103;&#97;\" title=\"Rendered by QuickLaTeX.com\" height=\"12\" width=\"30\" style=\"vertical-align: 0px;\"\/>\u00a0\u00a0load? How would this impact on quiescent power consumption?<\/li>\n<\/ul>\n<p>Comment on the suitability of a voltage divider as a power supply.<\/p>\n<figure id=\"attachment_276\" aria-describedby=\"caption-attachment-276\" style=\"width: 560px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-large wp-image-276\" src=\"http:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-1024x600.png\" alt=\"\" width=\"560\" height=\"328\" srcset=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-1024x600.png 1024w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-300x176.png 300w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-768x450.png 768w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-560x328.png 560w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-260x152.png 260w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel-160x94.png 160w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/PowerSupplyModel.png 1812w\" sizes=\"auto, (max-width: 560px) 100vw, 560px\" \/><figcaption id=\"caption-attachment-276\" class=\"wp-caption-text\">The component inside the dashed border represent a real voltage source, with ideal voltage source V and internal resistance Rint. The resister RL represents the <strong>load resistance<\/strong>. The actual voltage output Vout is calculated using the equation for a <strong>potential divider<\/strong>.<\/figcaption><\/figure>\n<figure id=\"attachment_277\" aria-describedby=\"caption-attachment-277\" style=\"width: 400px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-277\" src=\"http:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv-300x228.png\" alt=\"\" width=\"400\" height=\"303\" srcset=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv-300x228.png 300w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv-560x425.png 560w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv-260x197.png 260w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv-160x121.png 160w, https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-content\/uploads\/sites\/94\/2018\/09\/TheveninEquiv.png 758w\" sizes=\"auto, (max-width: 400px) 100vw, 400px\" \/><figcaption id=\"caption-attachment-277\" class=\"wp-caption-text\">Th\u00e9venin Equivalent Circuit for the 2.2V voltage source<\/figcaption><\/figure>\n<h2><b>References<\/b><\/h2>\n<p>[1] Ohms Law, BBC BiteSize, <a href=\"http:\/\/www.bbc.co.uk\/schools\/gcsebitesize\/science\/edexcel_pre_2011\/electricityintheory\/voltagecurrentresistancerev3.shtml\" target=\"_blank\" rel=\"noopener\">http:\/\/www.bbc.co.uk\/schools\/gcsebitesize\/science\/edexcel_pre_2011\/electricityintheory\/voltagecurrentresistancerev3.shtml<\/a>, accessed 27\/09\/2018<\/p>\n<p>[2] Voltage divider tutorial., <a href=\"https:\/\/www.youtube.com\/watch?v=XxLKfAZrhbM\" target=\"_blank\" rel=\"noopener\">https:\/\/www.youtube.com\/watch?v=XxLKfAZrhbM<\/a>, accessed 27\/09\/2018<\/p>\n<p>[3] Voltage Dividers, <a href=\"https:\/\/www.youtube.com\/watch?v=AyB2kXThlvE\" target=\"_blank\" rel=\"noopener\">https:\/\/www.youtube.com\/watch?v=AyB2kXThlvE<\/a>, accessed 27\/09\/2018<\/p>\n<p>[4] Th\u00e9venin&#8217;s theorem., <a href=\"https:\/\/en.wikipedia.org\/wiki\/Th%C3%A9venin's_theorem\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/Th\u00e9venin%27s_theorem<\/a>,accessed 27\/09\/2018<\/p>\n<hr \/>\n<h1>Feedback<\/h1>\n<p>If you wish to leave feedback or have a question, please use the form below.<\/p>\n<p>[contact-form][contact-field label=&#8221;Name&#8221; type=&#8221;name&#8221;  required=&#8221;true&#8221; \/][contact-field label=&#8221;Email&#8221; type=&#8221;email&#8221; required=&#8221;true&#8221; \/][contact-field label=&#8221;Website&#8221; type=&#8221;url&#8221; \/][contact-field label=&#8221;Message&#8221; type=&#8221;textarea&#8221; \/][\/contact-form]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Back to ToC This is a task that requires you the learner to take responsibility for your learning.\u00a0You will be given a problem statement. In this problem statement are some highlighted key terms \/ jargon. It is your task to research these terms in order to understand the problem and to attempt to solve it.&hellip; <a class=\"more-link\" href=\"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/microcontrollers\/mbed-os-2\/courses\/embedded-systems-in-context-level-4\/topic-2-potential-dividers-problem-based-learning-task\/\">Continue reading <span class=\"screen-reader-text\">Topic 2 &#8211; Potential Dividers (Problem Based Learning task)<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":130,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-272","page","type-page","status-publish","hentry","entry"],"_links":{"self":[{"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/pages\/272","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/comments?post=272"}],"version-history":[{"count":9,"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/pages\/272\/revisions"}],"predecessor-version":[{"id":493,"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/pages\/272\/revisions\/493"}],"up":[{"embeddable":true,"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/pages\/130"}],"wp:attachment":[{"href":"https:\/\/blogs.plymouth.ac.uk\/embedded-systems\/wp-json\/wp\/v2\/media?parent=272"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}