In a circuit using negative logic, which signal level represents a true condition?

In a circuit using negative logic, which signal level represents a true condition?

• A. Logical low (0)
• B. Logical high (1)
• C. Both levels equally represent true
• D. Neither level represents true

Answer: (A)

In negative logic, true is indicated by a low voltage level, not a high one. The logic is inverted compared with positive logic, so a low level (logical 0) is considered the asserted or true condition, while a high level (logical 1) is considered false. This is common for active-low control signals, such as an active-low reset, which is asserted when the line is low. Therefore, the true condition is represented by logical low. High would be treated as not true, and options claiming both levels or neither level represent true don’t fit this inverted interpretation.

In negative logic, true is indicated by a low voltage level, not a high one. The logic is inverted compared with positive logic, so a low level (logical 0) is considered the asserted or true condition, while a high level (logical 1) is considered false. This is common for active-low control signals, such as an active-low reset, which is asserted when the line is low. Therefore, the true condition is represented by logical low. High would be treated as not true, and options claiming both levels or neither level represent true don’t fit this inverted interpretation.