Subelement E: Digital Logic— Topic 35: Logic Levels
Question 3-35E1
Element 3 (GROL)In a negative-logic circuit, what level is used to represent a logic 0?
Explanation
In a negative-logic circuit, the convention for assigning voltage levels to logic states is inverted compared to the more common positive-logic system.
In standard (positive) logic, a high voltage level typically represents a logic 1, and a low voltage level represents a logic 0. However, in a negative-logic system, these assignments are reversed. Therefore, a low voltage level is used to represent a logic 1, and consistently, a **high voltage level is used to represent a logic 0**.
Options B and C refer to "transition levels," which describe changes in voltage over time (e.g., rising or falling edges), not the static voltage levels that define a logic state. Option A, a low level, would represent a logic 1 in a negative-logic system.
Related Questions
3-34E5 What is a characteristic of a NOT gate?3-34E6 Which of the following logic gates will provide an active high out when both inputs are active high?3-35E2 For the logic input levels shown in Figure 3E12, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)3-35E3 For the logic input levels given in Figure 3E13, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)3-35E4 In a positive-logic circuit, what level is used to represent a logic 1?