What method does an SD card use for storing data? A Magnetic disks and platters B Magnetic tape C Reflective surface and optical readers D Non-volatile memory chips
The Correct Answer and Explanation is :
Correct Answer: D. Non-volatile memory chips
Explanation:
An SD (Secure Digital) card uses non-volatile memory chips to store data. This technology, typically referred to as flash memory, is designed to retain information even when the power is turned off. Here’s how it works and why it’s the best fit for SD cards:
1. Structure of SD Cards:
SD cards contain integrated circuits with flash memory chips. These chips are composed of millions (or billions) of transistors organized into a grid. Each transistor can store a bit of data (0 or 1) by controlling the flow of electrical charges.
2. Data Storage Mechanism:
Flash memory is based on a floating-gate transistor system:
- A floating gate traps electrons to represent data.
- The presence or absence of trapped electrons determines whether a bit is stored as 0 or 1.
- This process is achieved through tunneling or electrical programming, which ensures data remains intact without requiring a constant power supply.
3. Advantages:
- Durability: Unlike magnetic disks or tapes, SD cards lack moving parts, making them more resistant to physical shocks.
- Compact Design: Their small size and lightweight form factor make them ideal for portable devices like smartphones, cameras, and tablets.
- Reusability: Flash memory allows for rewriting and erasing data, providing flexibility for various applications.
4. Why Not Other Options?:
- A (Magnetic disks and platters): Used in hard drives, not SD cards.
- B (Magnetic tape): An older storage technology, not used in SD cards.
- C (Reflective surface and optical readers): Used in CDs/DVDs, not SD cards.
In summary, SD cards rely on non-volatile memory chips due to their compactness, reliability, and ability to retain data without power, making them a versatile and widely-used storage medium.