In a full subtractor, the basic function is to subtract two binary digits and consider the borrow from the previous operation. A full subtractor has three inputs:
1. **Minuend (A)** - The digit being subtracted from.
2. **Subtrahend (B)** - The digit that is being subtracted.
3. **Borrow-in (Bin)** - The borrow from the previous less significant bit (if any).
It has two outputs:
- **Difference (D)** - The result of the subtraction.
- **Borrow-out (Bout)** - The borrow to the next more significant bit (if any).
### Integrated Circuit (IC) Used in Full Subtractor
For digital circuits like a full subtractor, **ICs (Integrated Circuits)** are used to implement logical gates such as AND, OR, XOR, and NOT gates, which are the building blocks of the full subtractor. While a full subtractor is typically constructed using individual gates, there are specific ICs that can help implement the required logic.
1. **7408 (AND Gate IC)**: This is a standard IC that provides AND gates, which are used to generate parts of the borrow logic in the full subtractor.
2. **7432 (OR Gate IC)**: This IC provides OR gates, which are used in the logic of generating the final borrow-out signal.
3. **7486 (XOR Gate IC)**: XOR gates are crucial in generating the difference and part of the borrow logic in the full subtractor. The XOR gate handles the case where the minuend and subtrahend bits are unequal, producing a "1" for a difference.
4. **7404 (NOT Gate IC)**: NOT gates are used to invert signals in the full subtractor's logic. In particular, they can be used to complement the inputs to form the required borrow-out logic.
### Logic for Full Subtractor
A full subtractor works using the following Boolean equations for the outputs:
- **Difference (D)** = A â B â Bin (XOR of A, B, and Borrow-in)
- **Borrow-out (Bout)** = (ÂŽA ⧠B) âĻ ((B â A) ⧠Bin) (Borrow-out depends on conditions involving A, B, and Borrow-in)
So, to build a full subtractor, a combination of XOR, AND, OR, and NOT gates is needed, which can be provided by the corresponding ICs.
### Conclusion
In practice, **no single IC is dedicated solely to the full subtractor**. However, **logic gate ICs like the 7408 (AND), 7432 (OR), 7486 (XOR), and 7404 (NOT)** can be used to construct a full subtractor. These ICs allow you to implement the necessary logic for performing binary subtraction with borrow handling.