Which component is typically not utilized in TTL logic circuits?

In TTL (Transistor-Transistor Logic) circuits, the fundamental building blocks are bipolar junction transistors (BJTs), which are used to create logic gates and other digital components. The primary components in TTL are transistors, resistors, and sometimes diodes for input/feedback stabilization.

Operational amplifiers, however, are not typically used in TTL logic circuits. They are designed for analog signal processing and have characteristics that are not aligned with the digital logic applications that TTL is meant for. Op-amps are used in applications requiring amplification of analog signals rather than in constructing digital logic gates, which is the primary purpose of TTL circuits.

While resistors play a vital role in biasing and current limiting in TTL, and transistors are the core elements for logic functions, diodes may be present in some configurations but are also not a defining component of standard TTL design. Therefore, the operational amplifier stands out as typically not utilized within TTL logic circuits, as its functionality differs significantly from what is required in digital logic circuitry.