Microprocessor Theory

Microprocessors run computers.

Microprocessors are the central hardware that run computers. There are several components that make a processor. The first is the transistor. Next, are logic gates where you put more than one transistor to work with others. The processors use binary math to perform operations. Finally, the microprocessors are developed using the process of lithography.

Transistors

The design and demonstration of the first transistors occurred at Bell Labs in New Jersey in 1947. A demonstration of the transistor effect was possible when different materials were put together with a semi-conductor to allow an electrical current to flow.

The transistor consists of three distinct layers, a conductor, a base, and an emitter. A transistor is like a light switch. When the switch is on (1), electricity flows through it. When the switch is off (0), no electricity flows.

Logic Gates

By themselves, transistors are not very functional. However, if you combine them with other transistors, you get logic gates. Logic gates carry out the instructions, mathematical or otherwise, that a processor performs. When you connect a variety of logic gates together, the results are interesting. You can create an AND or OR gate. Both will have 2 inputs and 1 output. For an AND gate, the output is always 0 unless both inputs are 1. With an OR gate, the output is 0 unless one OR both inputs are 1.

Binary Math or Base 2 Operations

All computer operations are done with binary values. This is a value of 1 or a 0 is what a processor performs with. Computer processors are 8 bits or 16, or 32, or 64 bits in size. An instruction that enters the microprocessor will fit one of those sizes. However, most modern microprocessors will be in the 32 or 64 bit range. There are 128 bit CPU's in the design phase, but they will not work effectively unless there are other hardware peripherals that are designed to handle instruction sets of that size.

Lithography

The fabrication of a microprocessor occurs on a semiconductor substrate. The term, substrate, refer to the base materials to which additional materials are added. The substrate is part of the silicon wafer where dies are cut, and it is the electrical grounding.

In general, you need three elements to make the microprocessor: film deposition, patterning, and semiconductor doping. Film deposition operate on both conductors and insulators to isolate and connect transistors and their components. Selective doping of different silicon regions allows conductivity of the silicon to be changed by applying voltage. However, lithography is key. It is the formation of a three-dimensional relief image on the substrate with a subsequent transfer of the pattern to the microprocessor that unifies them.

Summary

Microprocessor theory involves understanding the transistor, the logic gates, the binary math, and the lithography to create the chips. The transistor is fundamental because it carries an electrical charge and can direct the current flow through the logic gates. The microprocessor works with binary arithmetic. The microprocessor is created using a substrate where patterns are made and become the basis of the semiconductor. This process is lithography.

References

• How Does a Microprocessor Work?
• Lithography
• Microprocessors
• History of Microprocessors
• Basics of how does a transistor work

Resources

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