Correct option is D
When a digital electronics application needs high storage capacity at low cost, the best choice is Dynamic Random Access Memory (DRAM). DRAM stores each bit using a capacitor and transistor, so it packs more bits per chip area than SRAM, making it cheaper per bit and suitable for large memories. Although DRAM needs periodic refresh, it is widely used as main memory because of its capacity and cost advantages. SRAM is faster but expensive and lower density. Hence, the correct answer is (d) Dynamic Random Access Memory.
Information Booster
- Why DRAM is cost-effective? Uses 1 transistor + 1 capacitor per bit, giving high density and low cost/bit.
- Major Use: Main memory (RAM) in computers, embedded boards requiring larger memory, graphics memory (variants).
- Key Feature: Needs refresh cycles because capacitors leak charge over time.
- Comparison with SRAM:
- SRAM: Faster, no refresh, but expensive (typically ~6 transistors per bit).
- DRAM: Slower than SRAM, needs refresh, but much higher capacity and cheaper.
- Advantages of DRAM: High capacity, low cost per bit, widely available.
- Disadvantages of DRAM: Refresh overhead, relatively slower access, more complex control circuitry.
Additional Knowledge
- (a) EPROM — Incorrect: Non-volatile memory used for firmware/storage, not ideal for large low-cost working memory; also slower and not typically used as high-capacity RAM.
- (b) ROM — Incorrect: ROM is read-mostly/non-volatile; used to store fixed programs, not as high-capacity low-cost working memory like RAM.
- (c) SRAM — Incorrect: Very fast and no refresh, but costlier and lower density, so not best for high capacity at low cost.
