{"id":4477,"date":"2025-03-11T16:08:07","date_gmt":"2025-03-11T10:38:07","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=4477"},"modified":"2025-07-16T14:19:07","modified_gmt":"2025-07-16T08:49:07","slug":"basic-gates","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/ee\/boolean-algebra\/basic-gates","title":{"rendered":"Basic Gates"},"content":{"rendered":"<h2 style=\"text-align: justify;\">The NOT Gate<\/h2>\n<ul style=\"text-align: justify;\">\n<li>The NOT gate has a single input variable and a single output variable.<\/li>\n<li>The NOT operation is also referred to as \u2018INVERSION\u2019 or \u2018COMPLEMENTATION\u2019.<\/li>\n<li>Thus, its output logic level is always opposite to the logic level of its input.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4478 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/the-not-gate.jpg\" alt=\" The NOT Gate \" width=\"594\" height=\"129\" srcset=\"https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/the-not-gate.jpg 594w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/the-not-gate-300x65.jpg 300w\" sizes=\"auto, (max-width: 594px) 100vw, 594px\" \/><\/p>\n<ul style=\"text-align: justify;\">\n<li>The switching circuit and transistor circuit for a NOT gate are shown below.<br \/>\n\u21d2 When switch A is open i.e. logic \u20180\u2019 then, the bulb glows (shows logic \u20181\u2019).<br \/>\n\u21d2 When switch is closed i.e. logic \u20181\u2019 then, the bulb does not glow (shows logic \u20180\u2019).<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4479 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/transistor-circuit.jpg\" alt=\"Transistor Circuit\" width=\"579\" height=\"402\" srcset=\"https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/transistor-circuit.jpg 579w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/transistor-circuit-300x208.jpg 300w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/transistor-circuit-392x272.jpg 392w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/transistor-circuit-130x90.jpg 130w\" sizes=\"auto, (max-width: 579px) 100vw, 579px\" \/><\/p>\n<p style=\"text-align: justify;\"><strong> Note:<\/strong> Buffers are used to increase the driving capacity of a gate.<\/p>\n<ul style=\"text-align: justify;\">\n<li style=\"text-align: justify;\">Odd number of NOT gates\/inverters connected in feedback act like an astable multivibrator or, a square wave generator, or a clock pulse generator or, a free running oscillator.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4480 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/propagation_delay.jpg\" alt=\"Propagation Delay\" width=\"459\" height=\"219\" srcset=\"https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/propagation_delay.jpg 459w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/propagation_delay-300x143.jpg 300w\" sizes=\"auto, (max-width: 459px) 100vw, 459px\" \/><\/p>\n<h3 style=\"text-align: justify;\">The AND Gate<\/h3>\n<ul style=\"text-align: justify;\">\n<li>The AND gate can have two or more inputs but only one output.<\/li>\n<li>The logic symbol and the truth table of a two input AND gate are,<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4481 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/logical_expression.jpg\" alt=\"Logical Expression\" width=\"282\" height=\"155\" \/><\/p>\n<ul style=\"text-align: justify;\">\n<li>The logical expression is Y = AB<\/li>\n<li>It is clear from the truth table that, if all the inputs or any of the input is LOW (logic \u20180\u2019) the output is also at logic \u20180\u2019. However the output is 1 only when all the inputs are 1.<\/li>\n<li>AND gate follows both commutative and associative law as:<br \/>\n(i) Commutative law: AB = BA<br \/>\n(ii) Associative law: ABC = (AB)C = A(BC)<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-4482 aligncenter\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/commutative_law.jpg\" alt=\" Commutative law\" width=\"192\" height=\"87\" \/><\/p>\n<h4 style=\"text-align: justify;\">Enable and disable inputs:<\/h4>\n<p style=\"text-align: justify;\">For AND operations<\/p>\n<ul style=\"text-align: justify;\">\n<li style=\"list-style-type: none;\">\n<ul>\n<li><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4483 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/disable_input.jpg\" alt=\"Disable Input\" width=\"579\" height=\"428\" srcset=\"https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/disable_input.jpg 579w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/disable_input-300x222.jpg 300w\" sizes=\"auto, (max-width: 579px) 100vw, 579px\" \/>The bulb will glow only when both the switches A and B are closed or at logic \u20181\u2019.<br \/>\n\u2022 The AND operation is performed exactly like ordinary multiplication of 1\u2019s and 0\u2019s.<br \/>\n\u2022 In multi input AND gate, the unused input can be connected to<br \/>\n(i) Logic \u20181\u2019 or pull up (enable)<br \/>\n(ii) One of the used input<br \/>\n(iii) Left open for TTL logic circuit<br \/>\nOut of these three procedure the best way is to connect the logic \u20181\u2019 or pull up.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><strong>Note:<\/strong><\/p>\n<ul style=\"text-align: justify;\">\n<li>In ECL logic family, open or floating input will act as logic \u20180\u2019.<\/li>\n<li>In TTL logic family, open or floating input will act as logic \u20181\u2019.<\/li>\n<\/ul>\n<h3 style=\"text-align: justify;\">The OR Gate<\/h3>\n<ul style=\"text-align: justify;\">\n<li>The OR gate can have two or more inputs but only one output. The logic symbol and the truth table for OR gate are,<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-4486 aligncenter\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/the-or-gate.jpg\" alt=\" The OR Gate \" width=\"282\" height=\"144\" \/><\/p>\n<ul style=\"text-align: justify;\">\n<li>Thus, the logical expression is Y = A + B<\/li>\n<li>It is clear from the truth table that, if all the inputs or any of the input is high logic \u20181\u2019 the output Y is HIGH logic \u20181\u2019. Where as if all the inputs are LOW logic \u20180\u2019 then the output Y is low logic \u20180\u2019.<\/li>\n<li>OR gate follows both commutative and associative laws as:<br \/>\n(i) Commutative law: A + B = B + A<br \/>\n(ii) Associative law: (A + B + C) = (A + B) + C = A + (B + C)<\/li>\n<\/ul>\n<h4 style=\"text-align: justify;\">Enable and disable inputs:<\/h4>\n<p style=\"text-align: justify;\">For an OR gate<\/p>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4488 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/disable_inputs.jpg\" alt=\"Disable Inputs\" width=\"584\" height=\"309\" srcset=\"https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/disable_inputs.jpg 584w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/disable_inputs-300x159.jpg 300w, https:\/\/www.madeeasy.in\/study\/wp-content\/uploads\/2025\/03\/disable_inputs-390x205.jpg 390w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/p>\n<ul style=\"text-align: justify;\">\n<li>The switching circuit diagram for OR gate is,<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-4489 size-full\" src=\"https:\/\/study.madeeasy.in\/wp-content\/uploads\/2025\/03\/circuit_diagram-.jpg\" alt=\"Circuit Diagram \" width=\"238\" height=\"127\" \/><br \/>\nHere, the bulb will glow when any of the switch (either A or B), or both the switches are closed.<\/p>\n<ul>\n<li style=\"text-align: justify;\">In a multi input OR gate an unused input can be connected to<br \/>\n(i) Logic \u20180\u2019 (Enable) or pull-down.<br \/>\n(ii) Any of the used input.<br \/>\n(iii) Left open or floating in case of ECL logic.<br \/>\nOut of these procedures, the best way is to connected to the logic \u20180\u2019 or pull down.<\/li>\n<\/ul>\n<p style=\"text-align: center;\"><a class=\"btn btn-danger\" role=\"button\" href=\"https:\/\/study.madeeasy.in\/ee\/boolean-algebra\/logic-gates\/\" target=\"_blank\" rel=\"noopener\">&lt;&lt; Previous<\/a> | <a class=\"btn btn-success\" role=\"button\" href=\"https:\/\/study.madeeasy.in\/ee\/boolean-algebra\/the-nand-gate\/\" target=\"_blank\" rel=\"noopener\"> Next &gt;&gt;<\/a><br \/>\n<strong> Must Read: <\/strong> <a href=\"https:\/\/study.madeeasy.in\/subjects\/what-is-boolean-algebra\" target=\"_blank\" rel=\"noopener\"><strong>What is Boolean algebra?<\/strong><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The NOT Gate The NOT gate has a single input variable and a single output variable. The NOT operation is<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1291,5],"tags":[1449,1452,1454,1436,1455,1453,1451,1450,1314,1313,1315],"class_list":["post-4477","post","type-post","status-publish","format-standard","hentry","category-boolean-algebra","category-ee","tag-and-gate","tag-basic-gates-digital","tag-boolean-gates","tag-digital-logic","tag-electronics-fundamentals","tag-logic-gates-basics","tag-not-gate","tag-or-gate","tag-propagation-delay","tag-the-not-gate","tag-the-or-gate"],"_links":{"self":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/4477","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/comments?post=4477"}],"version-history":[{"count":0,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/4477\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/media?parent=4477"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/categories?post=4477"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/tags?post=4477"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}