Which of the following gates gives output 1 when any one of the input is 1?
Understanding Logic Gates and Their Outputs
Logic gates are fundamental building blocks of digital circuits. They perform basic logical operations on one or more binary inputs (typically 0 or 1) and produce a single binary output.
The question asks to identify the logic gate that produces an output of 1 when *any* of its inputs is 1. Let's examine the behavior of the given options:
Analyzing the Behavior of Different Logic Gates
OR Gate Logic
An OR gate outputs 1 if at least one of its inputs is 1. It only outputs 0 if all inputs are 0. This directly matches the condition described in the question.
Let's look at the truth table for a two-input OR gate (Inputs A and B, Output Q):
| Input A | Input B | Output Q (A OR B) |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
As the truth table shows, the output Q is 1 when either Input A is 1, Input B is 1, or both are 1. The output is only 0 when both inputs are 0.
NOT Gate Logic
A NOT gate is an inverter. It has only one input and reverses its state. If the input is 0, the output is 1; if the input is 1, the output is 0.
Truth Table for NOT gate (Input A, Output Q):
| Input A | Output Q (NOT A) |
|---|---|
| 0 | 1 |
| 1 | 0 |
The NOT gate does not fit the description, as its output depends solely on a single input's state, not whether "any one of the inputs" (implying multiple inputs) is 1.
NOR Gate Logic
A NOR gate is a combination of an OR gate and a NOT gate. It outputs 0 if at least one of its inputs is 1. It only outputs 1 if all inputs are 0. It is the opposite of an OR gate.
Truth Table for two-input NOR gate (Inputs A and B, Output Q):
| Input A | Input B | Output Q (A NOR B) |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
The NOR gate gives an output of 1 only when *none* of the inputs are 1, which is the opposite of the condition in the question.
AND Gate Logic
An AND gate outputs 1 only if *all* of its inputs are 1. If even one input is 0, the output is 0.
Truth Table for two-input AND gate (Inputs A and B, Output Q):
| Input A | Input B | Output Q (A AND B) |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
The AND gate outputs 1 only when *both* inputs are 1, not when *any one* is 1. This also does not match the condition.
Conclusion: Identifying the Correct Logic Gate
Comparing the behavior of each logic gate with the condition "gives output 1 when any one of the input is 1", we see that the OR gate is the one that satisfies this requirement. An OR gate outputs 1 whenever one or more of its inputs are 1.
Revision Table: Key Logic Gate Functions
| Logic Gate | Symbol | Condition for Output 1 |
|---|---|---|
| OR | >figure of an OR gate symbol goes here< | When any input is 1 (or all inputs are 1) |
| AND | >figure of an AND gate symbol goes here< | When all inputs are 1 |
| NOT | >figure of a NOT gate symbol goes here< | When the single input is 0 |
| NOR | >figure of a NOR gate symbol goes here< | When all inputs are 0 |
| NAND | >figure of a NAND gate symbol goes here< | When any input is 0 (or all inputs are 0) |
| XOR (Exclusive OR) | >figure of an XOR gate symbol goes here< | When an odd number of inputs is 1 |
Additional Information on Logic Gates
- Logic gates are typically implemented using transistors in integrated circuits.
- Basic gates are AND, OR, and NOT.
- Universal gates are NAND and NOR, as any logic function can be constructed using only one type of these gates.
- XOR and XNOR (Exclusive NOR) are also common logic gates used for specific functions like parity checking.
- Inputs and outputs of logic gates represent binary voltage levels, typically High (representing 1) and Low (representing 0).
Important Questions from Basic Gates
The NAND gate output will be low if the two inputs are-
Minimum number of NAND gates required to implement the following binary equation $Y = (A+B)(\overline{C \cdot D})$
Which of the following statements are true?
(i) Every logic network is equivalent to one using just NAND gates or just NOR gates.
(ii) Boolean expressions and logic networks correspond to labelled acyclic digraphs.
(iii) No two Boolean algebras with n atoms are isomorphic.
(iv) Non-zero elements of finite Boolean algebras are not uniquely expressible as joins of atoms.In a PLA, what components are used to implement the combinational logic functions?
Which of the following logic gates has output low when one of the inputs is high?
