{"id":186451,"date":"2025-01-25T07:52:59","date_gmt":"2025-01-25T07:52:59","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=186451"},"modified":"2025-01-25T07:53:01","modified_gmt":"2025-01-25T07:53:01","slug":"design-an-8-bit-comparator-using-a-two-numbers-of-ic-7485-or-using-a-nand-gates","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/25\/design-an-8-bit-comparator-using-a-two-numbers-of-ic-7485-or-using-a-nand-gates\/","title":{"rendered":"Design an 8 bit comparator using a two numbers of IC 7485 or using a NAND gates"},"content":{"rendered":"\n

Design an 8 bit comparator using a two numbers of IC 7485 or using a NAND gates.<\/p>\n\n\n\n

The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n

To design an 8-bit comparator using the IC 7485 or NAND gates, we need to understand the working of the comparator circuit.<\/p>\n\n\n\n

IC 7485 (4-bit Magnitude Comparator):<\/h3>\n\n\n\n

The IC 7485 is a 4-bit magnitude comparator that compares two 4-bit binary numbers and gives three output signals:<\/p>\n\n\n\n

    \n
  1. A>B<\/strong>: Output is high if input A is greater than input B.<\/li>\n\n\n\n
  2. A: Output is high if input A is smaller than input B.<\/strong><\/li>\n\n\n\n
  3. A=B<\/strong>: Output is high if both inputs A and B are equal.<\/li>\n<\/ol>\n\n\n\n

    Since the IC 7485 is a 4-bit comparator, for an 8-bit comparator, we can use two 7485 ICs in a cascaded configuration. Here\u2019s how to do that:<\/p>\n\n\n\n

    Step-by-Step Design:<\/h3>\n\n\n\n
      \n
    1. Divide the 8-bit inputs<\/strong> into two 4-bit groups. Let the 8-bit number A be A7A6A5A4A3A2A1A0 and the 8-bit number B be B7B6B5B4B3B2B1B0. We split these into two groups: A7A6A5A4 and A3A2A1A0 for number A, and B7B6B5B4 and B3B2B1B0 for number B.<\/li>\n\n\n\n
    2. Use two 7485 comparators<\/strong>:<\/li>\n<\/ol>\n\n\n\n
        \n
      • The first 7485 compares the most significant 4 bits (A7A6A5A4 with B7B6B5B4).<\/li>\n\n\n\n
      • The second 7485 compares the least significant 4 bits (A3A2A1A0 with B3B2B1B0).<\/li>\n<\/ul>\n\n\n\n
          \n
        1. Cascade the outputs<\/strong>: The outputs of the two ICs are then fed into logic gates that combine their results:<\/li>\n<\/ol>\n\n\n\n
            \n
          • The “A>B” output from both ICs are connected with an AND gate to give the overall “A>B” output.<\/li>\n\n\n\n
          • Similarly, the “A<B” outputs from both ICs are connected with an AND gate for the “A<B” output.<\/li>\n\n\n\n
          • The “A=B” outputs are connected with OR gates, combining the results of both 7485 ICs to determine if the entire 8-bit number A equals B.<\/li>\n<\/ul>\n\n\n\n

            Alternative Design Using NAND Gates:<\/h3>\n\n\n\n

            If you prefer to design the comparator using NAND gates, you’ll need to compare each pair of corresponding bits from the two numbers using XOR gates (since XOR will produce a “1” if the bits are different). Then, the results of XOR gates can be fed into a series of AND and OR gates to determine the overall comparison. Using only NAND gates requires constructing AND, OR, and NOT gates from NAND gates, and combining them appropriately.<\/p>\n\n\n\n

            This design ensures that the 8-bit comparator will provide accurate comparison results for both equality, greater than, and less than scenarios, using either the IC 7485 or logic gates like NAND gates.<\/p>\n","protected":false},"excerpt":{"rendered":"

            Design an 8 bit comparator using a two numbers of IC 7485 or using a NAND gates. The Correct Answer and Explanation is : To design an 8-bit comparator using the IC 7485 or NAND gates, we need to understand the working of the comparator circuit. IC 7485 (4-bit Magnitude Comparator): The IC 7485 is […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-186451","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/186451","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=186451"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/186451\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=186451"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=186451"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=186451"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}