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Hardware components of the PC The processor operates by using a set of binary ‘1’s and ‘0’s as data or instructions. The binary is represented by a voltage, with o volts representing a binary ‘0’ and a high voltage (usually between 2.5 volts and 5.0 volts) representing a binary ‘1’. These voltages operate on switches that are arranged as logic gates1 . In the early computers the switches were mechanical but today’s processors, and other parts of the circuit, use a transistor called a MOSFET (Metal oxide semiconductor field effect transistor). Millions of these MOSFETs can be created on a small piece of silicon, which can be manufactured into a circuit component called an Integrated circuit. The integrated circuit, or IC as it is commonly called, revolutionised the computer industry and produced the Microprocessor,or Processor as it is commonly called. Intel were the first company to integrate all the functions of a CPU on to a single IC; this was the 4004 microprocessor. The processor(CPU) works by processing calculations based on specific instructions that software2 running on the PC provides. These instructions, which are loaded into the processor when an application runs, tell the CPU how to manipulate chunks of data stored in the system’s main memory or Random Access Memory (RAM). This produces the desired result, whether it is adding boldface to text in a letter or changing the colour of a background in a scanned digital photo. The CPU is constantly churning through instructions and data that are loaded into it from the main memory. This is a brief description of what happens in a CPU, a more detailed description can be found by clicking on next below. [1] Logic Gates - see Appendix. [2] Software - a set of instructions that carry out a task. |