74xx logic families: How many independent 2-input NAND gates are contained inside a standard 7400 TTL IC (often called a “quad NAND”)?

Introduction / Context:
The 7400-series TTL family is a cornerstone of digital electronics. Part numbers encode both function and quantity. The 7400 device is a classic example, widely used in education and industry for simple logic building blocks.

Given Data / Assumptions:

• Device: 7400 TTL logic IC.
• Function: 2-input NAND gates packaged together.
• Package: 14-pin DIP in many versions.

Concept / Approach:
The 7400 is known as a 'quad 2-input NAND'. 'Quad' indicates four independent gates in one package. Pinouts show inputs and outputs mapped to four separate NAND sections, with Vcc and GND on standard pins (e.g., 14 and 7 in DIP packages).

Step-by-Step Solution:

Verification / Alternative check:
Compare to related devices: 7402 is quad 2-input NOR, 7404 is hex inverter (6 NOT gates), 7408 is quad 2-input AND. The pattern corroborates the 7400 having four NANDs.

Why Other Options Are Wrong:

• 1 or 2: Would be 'single' or 'dual,' not 7400.
• 8: That would be 'octal' and would not match pin constraints of a 14-pin DIP for 2-input gates.

Common Pitfalls:
Confusing 7400 with 7404 (hex inverters) or with CMOS 4000-series numbering. Always confirm the family and function from the part number.

Final Answer:
4