{"id":76,"date":"2025-10-28T11:08:44","date_gmt":"2025-10-28T04:08:44","guid":{"rendered":"https:\/\/phamquangvuong.com\/?p=76"},"modified":"2025-10-28T11:10:33","modified_gmt":"2025-10-28T04:10:33","slug":"dinh-luat-ohm-v-i-x-r","status":"publish","type":"post","link":"https:\/\/phamquangvuong.com\/en\/ohm-law\/","title":{"rendered":"Ohm&#8217;s Law \u2013 V = I \u00d7 R"},"content":{"rendered":"<p><\/p>\n<h2>1. Introduction<\/h2>\n<p>Ohm\u2019s Law describes the relationship between voltage (V), current (I), and resistance (R). It states that the current in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance. This is the foundation of all circuit analysis.<\/p>\n<h2>2. Basic Formula<\/h2>\n<p>The basic form of Ohm\u2019s Law is:<\/p>\n<pre><code>V = I \u00d7 R<\/code><\/pre>\n<p>From this, you can rearrange the formula to find the unknown quantity:<\/p>\n<pre><code>I = V \/ R\r\nR = V \/ I<\/code><\/pre>\n<h2>3. Example<\/h2>\n<p>Given a 12V power supply and a 6\u03a9 resistor:<\/p>\n<pre><code>I = V \/ R = 12 \/ 6 = 2A<\/code><\/pre>\n<p>Therefore, the current flowing through the resistor is 2 amperes.<\/p>\n<figure><a href=\"https:\/\/phamquangvuong.com\/wp-content\/uploads\/2025\/10\/ohm_law.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-73 size-medium\" src=\"https:\/\/phamquangvuong.com\/wp-content\/uploads\/2025\/10\/ohm_law-484x360.png\" alt=\"Ohm's Law graph showing Voltage vs Current for different resistances\" width=\"484\" height=\"360\" srcset=\"https:\/\/phamquangvuong.com\/wp-content\/uploads\/2025\/10\/ohm_law-484x360.png 484w, https:\/\/phamquangvuong.com\/wp-content\/uploads\/2025\/10\/ohm_law-768x571.png 768w, https:\/\/phamquangvuong.com\/wp-content\/uploads\/2025\/10\/ohm_law.png 799w\" sizes=\"auto, (max-width: 484px) 100vw, 484px\" \/><\/a><figcaption><em>Graph:<\/em> Relationship between voltage and current for various resistor values.<\/figcaption><\/figure>\n<h2>4. Practical Applications<\/h2>\n<ul>\n<li>Calculate a current-limiting resistor for an LED.<\/li>\n<li>Estimate current consumption for an Arduino or sensor circuit.<\/li>\n<\/ul>\n<h2>5. Practice Exercise<\/h2>\n<p><strong>Question:<\/strong> A 9V supply powers a 3\u03a9 resistor. Find the current and power dissipation.<\/p>\n<p><strong>Solution:<\/strong><\/p>\n<pre><code>I = V \/ R = 9 \/ 3 = 3A\r\nP = V \u00d7 I = 9 \u00d7 3 = 27W<\/code><\/pre>\n<h2>6. Additional Notes<\/h2>\n<p>Ohm\u2019s Law applies strictly to <em>linear components<\/em> such as resistors. Non-linear devices (like diodes and transistors) do not follow a straight-line V-I relationship; instead, they exhibit a curved response.<\/p>\n<h2>7. Conclusion<\/h2>\n<p>Ohm\u2019s Law is the foundation of electrical circuit analysis. Once you understand how voltage, current, and resistance interact, you can analyze and design virtually any basic circuit.<\/p>\n<h3>References<\/h3>\n<ul>\n<li>Thomas L. Floyd, <em>Electronics Fundamentals: Circuits, Devices, and Applications<\/em>, Pearson, 2014.<\/li>\n<li>Allan R. Hambley, <em>Electronics<\/em>, Prentice Hall, 2000.<\/li>\n<\/ul>\n<p><strong>Keywords:<\/strong> Ohm\u2019s Law, V=IR, voltage, current, resistance, electrical circuit, basic electronics<\/p>","protected":false},"excerpt":{"rendered":"<p>1. Introduction Ohm\u2019s Law describes the relationship between voltage (V), current (I), and resistance (R). It states that the current in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance. This is the foundation of all circuit analysis. 2. Basic Formula The basic form of Ohm\u2019s Law is: V [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14],"tags":[],"class_list":["post-76","post","type-post","status-publish","format-standard","hentry","category-dien-tu-co-ban"],"_links":{"self":[{"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/posts\/76","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/comments?post=76"}],"version-history":[{"count":3,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/posts\/76\/revisions"}],"predecessor-version":[{"id":79,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/posts\/76\/revisions\/79"}],"wp:attachment":[{"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/media?parent=76"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/categories?post=76"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/phamquangvuong.com\/en\/wp-json\/wp\/v2\/tags?post=76"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}