Question

Which of these devices use capacitors to store data?

• A. DRAM
• B. ERAM
• C. SRAM
• D. PRAM

Hint:

To remember memory characteristics:
- DRAM: Uses Capacitors \(\rightarrow\) Leaks charge \(\rightarrow\) Needs periodic Refreshing (used as main system RAM).
- SRAM: Uses Transistors (Flip-flops) \(\rightarrow\) No leaks \(\rightarrow\) No refresh needed (used as fast CPU Cache).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Computer memory (RAM) is classified into different types based on the physical electronic components used to store binary bits (0s and 1s).

Step 3: Detailed Explanation:
Let us examine the technology used in each type of memory listed:
- DRAM (Dynamic Random-Access Memory) - (A): This memory stores each bit of data in a separate integrated circuit cell containing a single transistor and a single tiny capacitor:
- The presence or absence of an electrical charge in the capacitor represents the binary states 1 or 0.
- Because capacitors slowly lose their electrical charge over time, the data would be lost if the charge was not periodically restored.
- To prevent this data loss, DRAM requires an external refresh circuit to read and rewrite the data hundreds of times per second, which is why it is called "dynamic."
- Let us analyze the other options:
- SRAM (Static Random-Access Memory) (C): This memory uses bistable latching circuitry (flip-flops made of 4 to 6 transistors) to store data.
SRAM does not use capacitors and does not need to be refreshed to maintain data, making it faster but more expensive than DRAM.
- PRAM (Phase-change RAM) (D): This non-volatile memory uses chalcogenide glass that changes state between crystalline and amorphous forms to store data.
Therefore, DRAM is the memory device that uses capacitors to store data.

Step 4: Final Answer:
The memory device that uses capacitors to store data is DRAM, matching Option (A).