Difficulty: Easy
Correct Answer: Correct
Explanation:
Introduction / Context:
The 7447 is a classic BCD-to-seven-segment decoder/driver used in introductory digital electronics. Understanding its input coding, output polarity, and auxiliary control pins is essential when interfacing counters or microcontrollers to seven-segment LED displays, particularly common-anode modules that expect active-LOW segment drive signals.
Given Data / Assumptions:
Concept / Approach:
The 7447 translates a BCD nibble into the appropriate segment pattern. Its outputs are active-LOW, meaning a logic 0 turns a segment on when used with a common-anode display. RBI/RBO allow cascaded blanking to automatically suppress leading zeros across multiple digits, improving readability without extra logic.
Step-by-Step Solution:
Verification / Alternative check:
Examine a typical 7447 truth table and pinout: outputs labeled a–g are open-collector, active-LOW; RBI/RBO pins are present for ripple blanking chains. Laboratory tests with a counter feeding the 7447 confirm correct segment patterns and blanking behavior.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing 7447 (active-LOW) with 7448 (active-HIGH); omitting required segment current limiting; forgetting that open-collector outputs may require pull-ups depending on wiring.
Final Answer:
Correct
Discussion & Comments