Suppose that you have an unknown two-input gate that is either an OR gate or an AND gate. What combination of input levels should you apply to the gate’s inputs to determine which type of gate it is?
Answer
A logic HIGH and a logic LOW applied to the inputs of the unknown 2-input gate would tell us what type of gate it is. If the resulting output logic level is HIGH then the gate is an OR gate. If the resulting output logic level is LOW. Then the gate is an AND gate.
The Correct Answer and Explanation is :
To determine whether a two-input gate is an OR gate or an AND gate, you can apply a combination of logic HIGH (1) and logic LOW (0) to the inputs of the gate. The behavior of the gate for different combinations of inputs will help identify its type. Here’s a detailed explanation of how this works.
Step-by-step approach:
- Input combination: Apply a logic HIGH (1) to one input and a logic LOW (0) to the other input. This combination will result in two different output possibilities depending on whether the gate is an OR gate or an AND gate.
- OR Gate:
- The OR gate outputs a logic HIGH (1) if at least one of its inputs is HIGH.
- For the input combination of (1, 0) or (0, 1), the output of the OR gate will be HIGH (1) because at least one input is 1.
- AND Gate:
- The AND gate outputs a logic HIGH (1) only when both inputs are HIGH.
- For the input combination (1, 0) or (0, 1), the output of the AND gate will be LOW (0) because both inputs are not HIGH.
Why this works:
- OR Gate Behavior: The OR gate outputs a HIGH when one or both inputs are HIGH. In this case, when we input a HIGH (1) and a LOW (0), the OR gate will output a HIGH (1).
- AND Gate Behavior: The AND gate only outputs a HIGH when both inputs are HIGH. If one input is LOW, the output will always be LOW, regardless of the other input’s state.
Conclusion:
By applying a combination of a logic HIGH and a logic LOW to the inputs of the unknown gate:
- If the output is HIGH (1), the gate is an OR gate.
- If the output is LOW (0), the gate is an AND gate.
This method efficiently distinguishes between an OR and an AND gate based on their differing logical behaviors.