BCD-to-7-segment 7447 outputs – if segment outputs a, b, c, d, and g are asserted (active), which digit appears on the display, and is it 5 as claimed?

Introduction / Context:
Seven-segment displays use segments labeled a through g to form numerals. The 7447 is a BCD-to-7-segment decoder/driver whose outputs correspond to these segments (with active-low drive for common-anode displays). This question checks whether lighting segments a, b, c, d, and g produces the numeral 5 or another digit.

Given Data / Assumptions:

• Segments are labeled a (top), b (upper-right), c (lower-right), d (bottom), e (lower-left), f (upper-left), g (middle).
• “Outputs active” means those segments are illuminated (active-low driver like 7447 pulls them on).
• Set considered: a, b, c, d, g are on; e and f are off.

Concept / Approach:
Draw or visualize the 7-segment layout. With a, b, c, d, and g illuminated, the display shows the top bar, both right-side bars, the bottom bar, and the middle bar. That pattern corresponds to the numeral 3. In contrast, the digit 5 requires a, f, g, c, and d—note that f (upper-left) is on and b is off for 5. Therefore, the statement claiming the displayed number is 5 is incorrect; it is actually 3.

Step-by-Step Solution:

Verification / Alternative check:
Reference segment maps in data sheets or standard charts; active-low nature of 7447 does not alter which segments must be lit—only the logic level required to light them.

Why Other Options Are Wrong:
0 lacks g; 7 lacks g and d; 9 requires f (upper-left) which is not active here; “5 as stated” conflicts with the actual segment pattern.

Common Pitfalls:
Forgetting which side segments b and f occupy; mixing common-cathode vs common-anode drive with the visual pattern.

Final Answer:
The digit is 3, not 5