In a negative-logic circuit, what level is used to represent a logic 0?

In a negative-logic circuit, a logic 0 is represented by a high level. This is based on the fundamental principle of negative logic, where the meanings of high and low voltage levels are inverted compared to positive logic. In positive logic, a high level generally represents a logic 1 and a low level represents a logic 0. However, in negative logic, these roles are reversed.

Therefore, when a high voltage level is present in a negative-logic configuration, it indicates that the signal is effectively in a logic 0 state. This approach is utilized in various digital systems and circuits for implementing specific logic functions or optimizing certain aspects of circuit performance. The other options do not correctly represent this concept within the context of negative logic.