Combinational Circuit - Adder Subtractor

Full Adder and Subtractor Circuit made from Integrated Circuit (IC) components to make a hardware calculator

Understanding Full and Half Adders and Subtractors in Combinational Circuits In this educational video, we delve into the fascinating world of combinational circuits, specifically focusing on full and half adders and subtractors. These fundamental components are essential in digital electronics, performing basic arithmetic operations.

• Half Adder: The half adder circuit performs simple addition of two single-bit binary numbers. It has two inputs (A and B) and two outputs: Sum and Carry. The Sum output is the XOR of the inputs, while the Carry output is the AND of the inputs.

• Full Adder: Building on the half adder, the full adder adds three single-bit binary numbers (including a carry-in from a previous addition). It has three inputs (A, B, and Carry-In) and two outputs: Sum and Carry-Out. The Sum output is calculated by XORing all three inputs, while the Carry-Out is derived from the OR of the ANDed inputs.

• Half Subtractor: This circuit subtracts one single-bit binary number from another, producing a Difference and a Borrow output. The Difference is the XOR of the inputs, and the Borrow is the AND of the negated minuend and the subtrahend.

• Full Subtractor: Extending the half subtractor, the full subtractor takes into account a Borrow-In from a previous subtraction. It has three inputs (Minuend, Subtrahend, and Borrow-In) and two outputs: Difference and Borrow-Out. The Difference output is obtained by XORing the inputs, while the Borrow-Out is calculated using a combination of logic gates.