Friday, November 23, 2007

RAM, Random Access Memory

This type of memory is essential for the working of a computer. It is a integrated chip consisting of rows and columns of a pair of transistor and a capacitor forming a grid. If the capacitor is charged at 50 % or more, it reflects a binary one. Due to the nature of a capacitor (it discharges at a very fast rate), it is required to charge them periodically. This is called a refresh cycle. In addition to the charging circuitry, it consists of a control circuit which is used to read and write data. Since the data can be accessed and written dynamically, these are called dynamic random access memory. The combined working of all the devices makes it slow in working.
Another type of RAM is the static RAM, where the integrated chip consists of a series of Flip-flops instead of a combination of a transistor and a capacitor. In the absence of a capacitor, there is no need to cater for the refresh cycle and this makes the static RAM considerably faster than a dynamic RAM. A Flip-flop consists of a few transistors and therefore the cost of a static RAM is higher, though it is compact.
By:Dean Barnard

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