Capacitors were used in the 1960s for computer memory, but dynamic RAM was patented by IBM in 1968. The first commercial chips came from Intel and Mostek in the early 1970s.
Dynamic RAM Is a Total Loser
The capacitors in a dynamic RAM chip are electrical storage tanks that do a poor job of holding a charge. They constantly leak, and the chip would lose its content even when the power is on if it were not for the refresh circuitry that continuously re-energizes the capacitors hundreds of times per second. However, even with the refresh circuitry, dynamic RAM cells take up significantly less space than static RAM cells. Contrast with static RAM. See memory types.
A Dynamic RAM Cell
DRAM cells are very simple. The combination of voltage on the row and column lines charges a capacitor. The only problem is that the capacitors keep losing their charges, and the bits must be read and re-written hundreds of times per second.
![]() | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2008 The Computer Language Company Inc. All rights reserved. |
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