{"id":157,"date":"2019-02-12T17:33:50","date_gmt":"2019-02-12T22:33:50","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/?post_type=chapter&#038;p=157"},"modified":"2020-01-13T16:17:41","modified_gmt":"2020-01-13T21:17:41","slug":"using-meters-for-simple-circuit-measurements","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/chapter\/using-meters-for-simple-circuit-measurements\/","title":{"raw":"Using Meters for Simple Circuit Measurements","rendered":"Using Meters for Simple Circuit Measurements"},"content":{"raw":"Electricity is something that cannot be seen. We can only see the effects of it.\r\n\r\nWhen a circuit is not operating correctly, it is very difficult to look at it and discover what is wrong.\r\n\r\nMeters are used to measure the effects of electricity.\u00a0Meters are precision instruments that can be damaged easily so certain precautions must be taken:\r\n<ul>\r\n \t<li>Shock and vibration should be avoided.<\/li>\r\n \t<li>Temperature, humidity, and dust should be considered.<\/li>\r\n \t<li>Magnetic fields: A tray magnetic field can cause inaccurate readings.<\/li>\r\n<\/ul>\r\n<strong>Precautions When Using Meters<\/strong>\r\n\r\nObserve the following precautions:\r\n<ul>\r\n \t<li>Never use an ohmmeter on a live circuit because an ohmmeter is its own power source. You will at best get an inaccurate reading, at worst damage the meter or yourself.<\/li>\r\n \t<li>Match the meter to the supply. If you are working with DC then use a DC meter; if working with AC then use an AC meter.<\/li>\r\n \t<li>When working with any DC meter, always observe proper polarity when connecting it to the circuit.<\/li>\r\n \t<li>Check that the meter is oriented correctly to be read. Some are meant to be read sitting up and others are meant to be read lying down.<\/li>\r\n \t<li>Read the meter looking straight at it to avoid parallax error.<\/li>\r\n \t<li>When finished with a meter, switch it off.<\/li>\r\n<\/ul>\r\n<strong>Voltmeters<\/strong>\r\n\r\n[caption id=\"attachment_183\" align=\"alignleft\" width=\"259\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/download.jpeg\" alt=\"\" width=\"259\" height=\"194\" class=\"size-full wp-image-183\" \/> Figure 21. Voltmeter[\/caption]\r\n\r\nVoltmeters are giant resistors that draw minimal current from the source. Voltmeters are meant to measure the potential difference between two points.\r\n\r\nThe meter must be connected in parallel with the load.\r\n\r\nIt is a good idea to test the voltmeter on a known circuit first.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<strong>Ammeters<\/strong>\r\n\r\n[caption id=\"attachment_184\" align=\"alignleft\" width=\"300\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter-300x200.jpg\" alt=\"\" width=\"300\" height=\"200\" class=\"size-medium wp-image-184\" \/> Figure 22. Clamp-on ammeter[\/caption]\r\n\r\nAmmeters are designed with low resistance so they do not add unwanted resistance to the circuit.\r\n\r\nConnect an ammeter in series with the circuit. If connected in parallel, it would cause a short circuit and blow the fuse in the meter.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<strong>Wattmeters<\/strong>\r\n\r\n[caption id=\"attachment_185\" align=\"alignleft\" width=\"221\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/221px-Wattmeter_geraet.jpg\" alt=\"\" width=\"221\" height=\"240\" class=\"size-full wp-image-185\" \/> Figure 23. Wattmeter[\/caption]\r\n\r\nThe wattmeter has four test leads. Two are for current and two are for voltage.\r\n\r\nPower is the product of both the voltage and the current so the wattmeter measures the effects of both and multiplies them to give the power.\r\n\r\nConnect the voltage coil in parallel with the load.\r\n\r\nConnect the current coil in series with the load.\r\n\r\nDo not exceed the power rating of the meter.\r\n\r\n<strong>Ohmmeters<\/strong>\r\n\r\n[caption id=\"attachment_186\" align=\"alignleft\" width=\"214\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg-214x300.jpg\" alt=\"\" width=\"214\" height=\"300\" class=\"size-medium wp-image-186\" \/> Figure 24. Ohmmeter image by Hannes Groebe. Used under Creative Commons Attribution-Share Alike 3.0 Unported license.[\/caption]\r\n\r\nOhmmeters are used to measure resistance. They have their own source of EMF (battery) and must not be used on a live circuit.\r\n\r\nThe scale on most ohmmeters reads backwards to other meters. Zero is on the right and infinity is on the left.\r\n\r\nMany ohmmeters will have a zero adjustment. Always zero the meter before using. Do this by shorting the two leads together.\r\n\r\n&nbsp;\r\n<h2><\/h2>\r\n<h2><\/h2>\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<strong>Electrical Meter Safety<\/strong>\r\n\r\nThe video below explains how not all electrical meters are created equal. Make sure you understand the ratings of your meter and what situations it can be used in.\r\n<div class=\"textbox textbox--exercises\"><header class=\"textbox__header\">\r\n<h2 class=\"textbox__title\" style=\"text-align: center\"><span style=\"color: #ffffff\">Video!<\/span><\/h2>\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n<div class=\"video-container\">\r\n\r\n[embed] https:\/\/youtu.be\/UTo6dny7EUY [\/embed]\r\n\r\n&nbsp;\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n<h2>Attribution<\/h2>\r\n<div id=\"content\" class=\"site-content\"><section class=\"standard post-65 chapter type-chapter status-publish hentry focusable\" data-type=\"chapter\"><a href=\"https:\/\/youtu.be\/UTo6dny7EUY\">Electrical Meter safety\u00a0<\/a>video by<span>\u00a0<\/span><a href=\"https:\/\/www.youtube.com\/channel\/UCRm79BcxKhOWRj6CQAB_Cqg\">The Electric Academy<\/a><span>\u00a0<\/span>is under a<span>\u00a0<\/span><a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">Creative Commons Attribution License<\/a>.<\/section><\/div>\r\n<nav class=\"nav-reading \" role=\"navigation\"><button class=\"nav-reading__up\"><span class=\"screen-reader-text\">BACK TO TOP<\/span><\/button><\/nav>","rendered":"<p>Electricity is something that cannot be seen. We can only see the effects of it.<\/p>\n<p>When a circuit is not operating correctly, it is very difficult to look at it and discover what is wrong.<\/p>\n<p>Meters are used to measure the effects of electricity.\u00a0Meters are precision instruments that can be damaged easily so certain precautions must be taken:<\/p>\n<ul>\n<li>Shock and vibration should be avoided.<\/li>\n<li>Temperature, humidity, and dust should be considered.<\/li>\n<li>Magnetic fields: A tray magnetic field can cause inaccurate readings.<\/li>\n<\/ul>\n<p><strong>Precautions When Using Meters<\/strong><\/p>\n<p>Observe the following precautions:<\/p>\n<ul>\n<li>Never use an ohmmeter on a live circuit because an ohmmeter is its own power source. You will at best get an inaccurate reading, at worst damage the meter or yourself.<\/li>\n<li>Match the meter to the supply. If you are working with DC then use a DC meter; if working with AC then use an AC meter.<\/li>\n<li>When working with any DC meter, always observe proper polarity when connecting it to the circuit.<\/li>\n<li>Check that the meter is oriented correctly to be read. Some are meant to be read sitting up and others are meant to be read lying down.<\/li>\n<li>Read the meter looking straight at it to avoid parallax error.<\/li>\n<li>When finished with a meter, switch it off.<\/li>\n<\/ul>\n<p><strong>Voltmeters<\/strong><\/p>\n<figure id=\"attachment_183\" aria-describedby=\"caption-attachment-183\" style=\"width: 259px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/download.jpeg\" alt=\"\" width=\"259\" height=\"194\" class=\"size-full wp-image-183\" srcset=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/download.jpeg 259w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/download-65x49.jpeg 65w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/download-225x169.jpeg 225w\" sizes=\"auto, (max-width: 259px) 100vw, 259px\" \/><figcaption id=\"caption-attachment-183\" class=\"wp-caption-text\">Figure 21. Voltmeter<\/figcaption><\/figure>\n<p>Voltmeters are giant resistors that draw minimal current from the source. Voltmeters are meant to measure the potential difference between two points.<\/p>\n<p>The meter must be connected in parallel with the load.<\/p>\n<p>It is a good idea to test the voltmeter on a known circuit first.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Ammeters<\/strong><\/p>\n<figure id=\"attachment_184\" aria-describedby=\"caption-attachment-184\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter-300x200.jpg\" alt=\"\" width=\"300\" height=\"200\" class=\"size-medium wp-image-184\" srcset=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter-300x200.jpg 300w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter-65x43.jpg 65w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter-225x150.jpg 225w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/320px-Clamp-on_ammeter.jpg 320w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-184\" class=\"wp-caption-text\">Figure 22. Clamp-on ammeter<\/figcaption><\/figure>\n<p>Ammeters are designed with low resistance so they do not add unwanted resistance to the circuit.<\/p>\n<p>Connect an ammeter in series with the circuit. If connected in parallel, it would cause a short circuit and blow the fuse in the meter.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Wattmeters<\/strong><\/p>\n<figure id=\"attachment_185\" aria-describedby=\"caption-attachment-185\" style=\"width: 221px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/221px-Wattmeter_geraet.jpg\" alt=\"\" width=\"221\" height=\"240\" class=\"size-full wp-image-185\" srcset=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/221px-Wattmeter_geraet.jpg 221w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/221px-Wattmeter_geraet-65x71.jpg 65w\" sizes=\"auto, (max-width: 221px) 100vw, 221px\" \/><figcaption id=\"caption-attachment-185\" class=\"wp-caption-text\">Figure 23. Wattmeter<\/figcaption><\/figure>\n<p>The wattmeter has four test leads. Two are for current and two are for voltage.<\/p>\n<p>Power is the product of both the voltage and the current so the wattmeter measures the effects of both and multiplies them to give the power.<\/p>\n<p>Connect the voltage coil in parallel with the load.<\/p>\n<p>Connect the current coil in series with the load.<\/p>\n<p>Do not exceed the power rating of the meter.<\/p>\n<p><strong>Ohmmeters<\/strong><\/p>\n<figure id=\"attachment_186\" aria-describedby=\"caption-attachment-186\" style=\"width: 214px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg-214x300.jpg\" alt=\"\" width=\"214\" height=\"300\" class=\"size-medium wp-image-186\" srcset=\"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg-214x300.jpg 214w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg-65x91.jpg 65w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg-225x316.jpg 225w, https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-content\/uploads\/sites\/549\/2019\/02\/Ohmmeter-bakelit-aeg_hg.jpg 342w\" sizes=\"auto, (max-width: 214px) 100vw, 214px\" \/><figcaption id=\"caption-attachment-186\" class=\"wp-caption-text\">Figure 24. Ohmmeter image by Hannes Groebe. Used under Creative Commons Attribution-Share Alike 3.0 Unported license.<\/figcaption><\/figure>\n<p>Ohmmeters are used to measure resistance. They have their own source of EMF (battery) and must not be used on a live circuit.<\/p>\n<p>The scale on most ohmmeters reads backwards to other meters. Zero is on the right and infinity is on the left.<\/p>\n<p>Many ohmmeters will have a zero adjustment. Always zero the meter before using. Do this by shorting the two leads together.<\/p>\n<p>&nbsp;<\/p>\n<h2><\/h2>\n<h2><\/h2>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Electrical Meter Safety<\/strong><\/p>\n<p>The video below explains how not all electrical meters are created equal. Make sure you understand the ratings of your meter and what situations it can be used in.<\/p>\n<div class=\"textbox textbox--exercises\">\n<header class=\"textbox__header\">\n<h2 class=\"textbox__title\" style=\"text-align: center\"><span style=\"color: #ffffff\">Video!<\/span><\/h2>\n<\/header>\n<div class=\"textbox__content\">\n<div class=\"video-container\">\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Electrical meter safety\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/UTo6dny7EUY?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<\/div>\n<\/div>\n<\/div>\n<h2>Attribution<\/h2>\n<div id=\"content\" class=\"site-content\">\n<section class=\"standard post-65 chapter type-chapter status-publish hentry focusable\" data-type=\"chapter\"><a href=\"https:\/\/youtu.be\/UTo6dny7EUY\">Electrical Meter safety\u00a0<\/a>video by<span>\u00a0<\/span><a href=\"https:\/\/www.youtube.com\/channel\/UCRm79BcxKhOWRj6CQAB_Cqg\">The Electric Academy<\/a><span>\u00a0<\/span>is under a<span>\u00a0<\/span><a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">Creative Commons Attribution License<\/a>.<\/section>\n<\/div>\n<nav class=\"nav-reading\" role=\"navigation\"><button class=\"nav-reading__up\"><span class=\"screen-reader-text\">BACK TO TOP<\/span><\/button><\/nav>\n","protected":false},"author":422,"menu_order":4,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-157","chapter","type-chapter","status-publish","hentry"],"part":29,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapters\/157","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/wp\/v2\/users\/422"}],"version-history":[{"count":25,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapters\/157\/revisions"}],"predecessor-version":[{"id":324,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapters\/157\/revisions\/324"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/parts\/29"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapters\/157\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/wp\/v2\/media?parent=157"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/pressbooks\/v2\/chapter-type?post=157"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/wp\/v2\/contributor?post=157"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/basicelectricity\/wp-json\/wp\/v2\/license?post=157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}