Lesson3_2.pdf - Adders Subtractors Lesson Objectives The...

  • No School
  • AA 1
  • 6

This preview shows page 1 - 3 out of 6 pages.

Adders - Subtractors Lesson Objectives: The objectives of this lesson are to learn about: 1. Half adder circuit. 2. Full adder circuit. 3. Binary parallel adder circuit. 4. Half subtractor circuit. 5. Full subtractor circuit. Half Adder: A half adder (HA) is an arithmetic circuit that is used to add two bits. The block diagram of HA is shown. It has two inputs and two outputs. The inputs of the HA are the 2 bits to be added; the augend, and addend. The output is the result of this addition, i.e. a sum bit (S) and a carry bit (C). INPUTS OUTPUTS X Y C S 0 0 0 0 0 1 0 1 1 0 0 1 1 1 1 0 The truth table of HA is shown. The Boolean functions for the two outputs can be obtained from the truth table which are: Y X Y X Y X S = + = ) ( XY C = Thus, the HA can be implemented using one XOR gate and one AND gate as shown in the Figure. Full Adder: A full adder (FA) is an arithmetic circuit that is used to add three bits. The block diagram of FA is shown. It has three inputs and two outputs.
Image of page 1

Subscribe to view the full document.

The inputs of the FA are the 3 bits to be added; the augend, addend, and carry from previous lower significant position. The output is the result of this addition, i.e. a sum bit (S) and a carry bit (C). INPUTS OUTPUTS X Y Z C S 0 0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 1 1 1 0 1 0 0 0 1 1 0 1 1 0 1 1 0 1 0 1 1 1 1 1 The truth table of FA is shown. The simplified Boolean functions for the two outputs can be obtained from the truth table, which are: Z Y X XYZ Z Y X Z Y X Z Y X S = + + + = YZ XZ XY C + + = The Boolean functions for the two outputs can be
Image of page 2
Image of page 3

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes