Memory technologies – identifying how dynamic RAM (DRAM) stores one bit In dynamic semiconductor memory (DRAM), a single data bit is stored as charge on which circuit element?

Introduction / Context:
This item checks core memory-technology knowledge: how dynamic random-access memory (DRAM) represents a single binary bit. Understanding the storage element explains why DRAM needs periodic refresh and how it differs from static RAM (SRAM) and register flip-flops.

Given Data / Assumptions:

• The device class is DRAM (dynamic RAM).
• We are considering the physical circuit element that retains a 0 or 1.
• Binary information is represented by the presence or absence of electric charge.

Concept / Approach:
In DRAM, each cell pairs a MOS access transistor with a tiny capacitor. A stored 1 corresponds to charge on the capacitor; a 0 corresponds to little or no charge. Because the charge leaks over time, DRAM must be refreshed periodically. This is fundamentally different from SRAM, which uses cross-coupled inverters (flip-flop like) to hold state as long as power is applied.

Step-by-Step Solution:

Verification / Alternative check:
Any DRAM cell schematic shows a single transistor connected to a storage capacitor; refresh specifications in datasheets further confirm charge-based storage.

Why Other Options Are Wrong:

• Diode: Not used as the storage element in DRAM cells.
• Resistor: Not the charge-holding component; resistors conduct but do not store charge like capacitors.
• Flip-flop: Flip-flops are used in SRAM/registers; DRAM does not use a bistable latch per bit.

Common Pitfalls:

• Confusing DRAM with SRAM and assuming a latch stores the bit.
• Overlooking the need for refresh, which is a direct consequence of capacitor leakage.

Final Answer:
capacitor