Sensors are based on which technology?

• A. Photomultiplier tubes
• B. Solid-state technology
• C. Vacuum tubes
• D. Mechanical gears

Answer: (B)

Solid-state technology, using semiconductors and integrated circuits, is the basis for most sensors today. Semiconductors allow sensing and signal processing to be done in tiny, reliable, low-power devices that can be mass-produced and easily integrated with digital systems. This makes sensors compact and robust for everyday electronics, robotics, and industrial use.

In contrast, devices like photomultiplier tubes are vacuum-tube-based and rely on electron amplification in a vacuum, which makes them bulky, voltage-hungry, and fragile for general sensing tasks. Vacuum tubes as a category have similar drawbacks and aren’t the practical foundation for modern sensors. Mechanical gears are purely mechanical and don’t inherently convert physical quantities into electrical signals, which is what sensors typically do in contemporary systems.