In a display, one key advantage of LCD displays over LEDs in meters is lower power consumption.

In a display, one key advantage of LCD displays over LEDs in meters is lower power consumption.

• A. Analog/digital circuits.
• B. Microprocessor circuitry.
• C. Opposing coils and a commutator.
• D. Parallel ports.

Answer: (B)

Lower power consumption with LCD displays comes from how they are driven. LCDs don’t emit light themselves; they modulate light from a backlight or from ambient illumination with very small switching currents. When the display is driven by a microcontroller with efficient, low-current drivers and multiplexed addressing, the overall power needed to light the display is much lower than lighting up many LED segments. That’s why the best choice points to the microprocessor circuitry—the display drive electronics controlled by the microprocessor—since it determines how much current the display requires. LED displays, in contrast, need LEDs to be lit, which draws more current and often requires more substantial driver circuitry, increasing power use. Analogue/digital circuits, opposing coils and a commutator, and parallel ports don’t directly explain the power difference in display types.

Lower power consumption with LCD displays comes from how they are driven. LCDs don’t emit light themselves; they modulate light from a backlight or from ambient illumination with very small switching currents. When the display is driven by a microcontroller with efficient, low-current drivers and multiplexed addressing, the overall power needed to light the display is much lower than lighting up many LED segments.

That’s why the best choice points to the microprocessor circuitry—the display drive electronics controlled by the microprocessor—since it determines how much current the display requires. LED displays, in contrast, need LEDs to be lit, which draws more current and often requires more substantial driver circuitry, increasing power use.

Analogue/digital circuits, opposing coils and a commutator, and parallel ports don’t directly explain the power difference in display types.