Which RAM type loses data when power is removed unless refreshed?

Which RAM type loses data when power is removed unless refreshed?

• A. DRAM
• B. SRAM
• C. MRAM
• D. Flash Memory

Answer: (A)

The key idea is how memory retains data when power is removed. Dynamic RAM (DRAM) stores each bit as charge on a tiny capacitor. Capacitors naturally leak charge, so the stored value fades unless it’s regularly refreshed by the memory controller. If power is removed, that refreshing cannot occur, so the data decays and is lost. That’s why DRAM requires ongoing refresh to keep data alive while power is present, and it is the RAM type described. Static RAM (SRAM) uses flip-flop circuits to hold bits and doesn’t rely on charging a capacitor, so it doesn’t need periodic refresh. However, it still loses data once power is gone. MRAM and flash memory are non-volatile; they retain data without continuous power, so they don’t fit the “needs refresh to preserve data” idea.

The key idea is how memory retains data when power is removed. Dynamic RAM (DRAM) stores each bit as charge on a tiny capacitor. Capacitors naturally leak charge, so the stored value fades unless it’s regularly refreshed by the memory controller. If power is removed, that refreshing cannot occur, so the data decays and is lost. That’s why DRAM requires ongoing refresh to keep data alive while power is present, and it is the RAM type described.

Static RAM (SRAM) uses flip-flop circuits to hold bits and doesn’t rely on charging a capacitor, so it doesn’t need periodic refresh. However, it still loses data once power is gone. MRAM and flash memory are non-volatile; they retain data without continuous power, so they don’t fit the “needs refresh to preserve data” idea.