74LS08 / 7408 quad 2-input AND gate – are VCC and GND on pins 14 and 7 powering all four gates?

Introduction / Context:
Standard 14-pin TTL logic ICs (e.g., 74xx series) use a common power pinout convention. Knowing supply pins is essential for prototyping and troubleshooting power issues across all internal gates.

Given Data / Assumptions:

• Device: 7408 (or 74LS08) quad two-input AND gate.
• Typical DIP-14 package.
• Standard TTL convention: VCC at pin 14, GND at pin 7.

Concept / Approach:
The IC houses four independent AND gates that share the same supply rails. Supplying VCC to pin 14 and GND to pin 7 powers the entire die, not just one gate. Individual gates are accessed through their respective input/output pins but all rely on the same VCC/GND pins.

Step-by-Step Solution:

Verification / Alternative check:
Datasheets and pinout diagrams consistently show the same assignment across many 74xx devices. Schematic symbols group four gates (A, B, C, D) but share the same power pins, simplifying board routing.

Why Other Options Are Wrong:
“Incorrect” contradicts datasheets. “Only two of the four gates are powered” has no basis in the design. “Depends on package subtype” is misleading; DIP and SOIC keep the same logical assignment. “Only in CMOS versions” is false; TTL and CMOS families alike follow the convention for 7408 variants.

Common Pitfalls:
Confusing per-gate pins with power pins or mixing up devices (e.g., thinking pin 8 is GND like on some 8-pin parts). Always verify with the device's pinout.

Final Answer:
Correct