What is multiple input logic gates?
Multi input gates can be made by joining gates of the same type with less inputs. The diagrams below shows how a three input AND gate and and a four input AND gate can be made out of two input AND gates.
The Use of Logic Gate
Adding more input terminals to a logic gate increases the number of input state possibilities. With a single-input gate such as the inverter or buffer, there can only be two possible input states: either the input is “high” (1) or it is “low” (0).
Most logic gates have two inputs and one output. Logic gates are based on Boolean algebra. At any given moment, every terminal is in one of the two binary conditions, false or true.
A digital logic gate can have more than one input, for example, inputs A, B, C, D etc., but generally only have one digital output, (Q).
Like the AND gate, the OR function can have any number of individual inputs. However, commercial available OR gates are available in 2, 3, or 4 inputs types.
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Digital Circuits Questions and Answers – Logic Gates and Networks – 1.
| INPUT | OUTPUT | |
|---|---|---|
| 1 | 0 | 0 |
| 1 | 1 | 1 |
Another type of special gate output is called tristate, because it has the ability to provide three different output modes: current sinking (“low” logic level), current sourcing (“high”), and floating (“high-Z,” or high-impedance).
Logic gates are used to carry out logical operations on single or multiple binary inputs and give one binary output. In simple terms, logic gates are the electronic circuits in a digital system.
The basic logic gates are classified into seven types: AND gate, OR gate, XOR gate, NAND gate, NOR gate, XNOR gate, and NOT gate. The truth table is used to show the logic gate function. All the logic gates have two inputs except the NOT gate, which has only one input.
3 Input OR Gate Truth Table. The output of a three-input OR Logic gate is zero if all the three inputs are at logic zero levels on the other hand the output is one if anyone/two/ three inputs are at logic high.
How many 2-input or gates are needed to implement 4 input OR gate?
The number of 2-input NAND gates required to implement a 2-input XOR gate is 4. Similarly, the number of 2-input NOR gates required to implement a 2-input XNOR gate is 4.
As with the AND function seen previously, the NAND function can also have any number of individual inputs and commercial available NAND Gate IC's are available in standard 2, 3, or 4 input types. If additional inputs are required, then the standard NAND gates can be cascaded together to provide more inputs for example.
The 74LS32 is a Dual Input OR Gate with Quad package. It contains four independent gates each of which performs the logic OR function. Each gate has two inputs that's why it is named Quad 2-Input OR Gate.