7402 Quad 2-Input NOR Gate IC (DIP)

7402 Quad 2-Input NOR Gate IC (DIP) — Overview

The 7402 Quad 2-Input NOR Gate IC is a classic TTL logic device in the 74xx family. It contains four independent two-input NOR gates packaged in a standard 14-pin DIP, offering fast switching and stable logic levels for digital circuit design, testing, and education. Because the NOR gate is universal, a 7402 can be used to build many other logic functions.

Key Benefits

• Four independent 2-input NOR gates in a single 14-pin DIP
• TTL compatibility ensures predictable timing and noise margins
• Breadboard-friendly DIP package simplifies prototyping and classroom use
• Flexible — can be combined to implement complex combinational and sequential logic

Technical Features and Specifications

• Part: 7402 (Quad 2-Input NOR Gate)
• Logic family: 74xx TTL
• Number of gates: 4 independent 2-input NOR gates
• Operating voltage: 4.75 V to 5.25 V (typical 5 V)
• Package: 14-pin Dual Inline Package (DIP)
• High-speed switching performance suitable for many digital applications

Truth Table (2-input NOR)

• A = 0, B = 0, Y = 1
• A = 0, B = 1, Y = 0
• A = 1, B = 0, Y = 0
• A = 1, B = 1, Y = 0

Pinout (14-pin DIP)

• Pin 1: 1A (Input)
• Pin 2: 1B (Input)
• Pin 3: 1Y (Output)
• Pin 4: 2A (Input)
• Pin 5: 2B (Input)
• Pin 6: 2Y (Output)
• Pin 7: GND (Ground)
• Pin 8: 3Y (Output)
• Pin 9: 3A (Input)
• Pin 10: 3B (Input)
• Pin 11: 4Y (Output)
• Pin 12: 4A (Input)
• Pin 13: 4B (Input)
• Pin 14: VCC (Positive Supply, typically +5 V)

Applications

• Digital logic circuit design and prototyping
• Control and decision-making circuits
• Combinational and sequential logic building blocks
• Educational electronics labs and training kits
• DIY digital electronics and embedded systems projects

Usage Tips and Best Practices

• Use a stable 5 V supply and decouple VCC to GND with a 0.1 µF ceramic capacitor near the chip for stable operation.
• Observe standard TTL input levels and avoid driving inputs beyond the supply rails.
• When prototyping on a breadboard, orient the DIP so pin 1 is at the marked corner and route power rails clearly to avoid wiring errors.
• For lower power or CMOS-level interfacing, consider CMOS equivalents like 74HC02 or 74HCT02 and check voltage compatibility.

Why Choose the 7402?

The 7402 remains a popular choice for teaching, hobbyist projects, and legacy system repairs because of its predictable TTL behavior, wide availability, and ease of use in DIP format. Its universal nature lets learners explore how NOR gates can form the basis for all digital logic functions.

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