Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 166 of 494
How many individual Light Emitting Diodes (LED segments) are arranged in a standard numeric seven-segment display to render decimal digits from 0 through 9?
A
7 LEDs (arranged in a figure-8 shape)
B
5 LEDs (arranged in a cross shape)
C
14 LEDs (arranged in concentric circles)
D
2 LEDs (arranged in parallel)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 7 LEDs (arranged in a figure-8 shape)
Concept:

A seven-segment display uses seven individual LED bars (labeled \( a \) through \( g \)) arranged in a figure-8 pattern. Selectively illuminating combinations of these segments displays all decimal digits from 0 to 9.

Formula:

$$\text{Segment Count} = 7 \quad (a, b, c, d, e, f, g) \quad [\text{excluding optional decimal point}]$$

Solution:

  • By lighting specific subsets of the 7 segments (e.g., segments \( b, c \) for digit '1', or segments \( a, b, c, d, e, f \) for digit '0'), any digit from 0 through 9 can be formed.


  • An optional 8th LED is often included for a decimal point (DP), but the main numeric display uses 7 primary segments.


Why other options are incorrect:

  • Option B: 5 segments cannot form standard alphanumeric numerals.
  • Option C: 14-segment displays are used for full alphanumeric text (letters and numbers), not standard 7-segment numeric displays.
  • Option D: 2 LEDs can only display binary states (0 and 1).

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