What symbol indicates a NOT gate in TPC schematics?

The symbol that indicates a NOT gate in TPC schematics is represented by a triangle with a small circle at the output. This design is consistent with the standard conventions for digital logic diagrams, where a triangle signifies the direction of signal flow, and the small circle indicates inversion. The presence of the circle at the output shows that the output is the logical negation of the input, effectively demonstrating that the NOT gate inverts the incoming signal. Thus, when the input is high, the output is low, and vice versa, which is fundamental to the operation of a NOT gate.

The other options depict different logic gate symbols or components that do not accurately represent a NOT gate according to standard schematic conventions. Understanding the distinct symbols used for different gates is essential for interpreting and designing logic circuits accurately.