Reading logic symbols — output bubbles/triangles In the shown memory/logic device, small inverted triangles (inverters) appear at the outputs. What do they indicate about the outputs?

Introduction / Context:Schematic symbols use small shapes to communicate logic polarity. A tiny inversion symbol at a pin tells you whether the external “active” level is a logical LOW or HIGH. This is crucial when interfacing memory or logic outputs to downstream circuits and buses.

Given Data / Assumptions:

• The symbol shows a small inversion marker (often a small triangle with a bubble, or a bubble) placed at the output pins.
• We are to infer the output's active polarity.
• No other special drive symbols (e.g., tri-state enable bars) are indicated.

Concept / Approach:

An inversion indicator denotes logical inversion between the internal node and the external pin. When placed on an output, it signals that the output is asserted at logical 0 (active-LOW). Datasheets often label such pins with a bar over the name (e.g., OE̅) or a trailing “#” or “/”.

Step-by-Step Solution:

Verification / Alternative check:

Cross-check with common logic symbols: input or output bubbles consistently mean active-LOW polarity; triangles alone can denote buffers or amplifiers but a bubble denotes inversion/active-LOW.

Why Other Options Are Wrong:

• High fan-out claim is a drive strength attribute, not a symbol for inversion.
• “Change-detect” behavior is unrelated to inversion symbols.
• Tristate is typically shown with an enable pin (often active-LOW) and not merely with inversion at outputs.

Common Pitfalls:

• Confusing tri-state capability with active-LOW polarity indicators.

Final Answer:

They represent inverters and mean that the outputs are active-LOW.