*Question E7A11:
What does “positive logic” mean in reference to logic devices?*  

*Correct Answer is  B: High voltage represents a 1, low voltage a 0*  

### AI Response: (may contain errors)  

In digital electronics, "positive logic" refers to a system where:

- A high voltage level represents a logical "1".
- A low voltage level represents a logical "0".

This is why the correct answer is **B: High voltage represents a 1, low voltage a 0**.

### Explanation:

1. **Correct Answer (B):**  
   - In positive logic systems, the higher voltage level is used to signify a logical "1", and the lower voltage level signifies a logical "0". This is a common convention in digital circuits and is intuitive because "high" often implies "on" or "true".

2. **Why Other Choices Are Incorrect:**
   - **A: The logic devices have high noise immunity**  
     - Noise immunity refers to a circuit's ability to withstand electrical noise without errors. While positive logic can be designed with good noise immunity, the term "positive logic" itself does not inherently imply high noise immunity.
   
   - **C: The logic circuit is in the “true” condition**  
     - The term "true condition" is not directly related to the concept of positive logic. Positive logic simply defines how voltage levels correspond to logical states, not the operational state of the circuit.
   
   - **D: 1s and 0s are defined as different positive voltage levels**  
     - This choice is misleading because it suggests that both logical states are represented by positive voltages. In positive logic, a "0" is typically represented by a low voltage, which may be close to zero or ground, not a positive voltage.

### Additional Notes:

- **Negative Logic:** In contrast, negative logic would use a high voltage to represent a "0" and a low voltage to represent a "1".
- **Voltage Levels:** The specific voltage levels that define "high" and "low" can vary depending on the technology (e.g., TTL, CMOS) but the principle of positive logic remains the same.