Posts by Farahat

Power Supplies It is surprising to many people that you can add a simple voltage regulator to power your projects for just a few dollars; cheaper than a set of rechargeable batteries. Voltage regulators, powered by an AC/DC ‘‘Wall wart’’ power converter, will convert one DC voltage to another that can be used by the […]
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Computer Processors and Support I’m sure that you realize that computer processors are really just a great big sequential circuit, but I’m sure that you have no idea where to start understanding how they work. Traditional computer processors are designed using a selection of six or so basic design philosophies that give them different characteristics. […]
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Reading Datasheets I’ve never understood why college and university courses do not give an introductory course in reading digital electronic device datasheets. Despite how prepared you are for them, you will feel quite overwhelmed the first time you have to look through a number of datasheets trying to find a part that meets your requirements. […]
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Pulse Width Modulation Despite showing how logic gates and other digital devices are built from simple analog components, they do not handle working with analog voltages very well. There are some circuits that will produce a valid analog (an arbitrary voltage, not just logic ‘‘high’’ and ‘‘low’’) voltage but they do not work very well […]
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Circuit Interfaces For a sequential digital electronic circuit to be effective, it has to interface with something. This something could be a person or it could be other digital electronic circuits. If you were to look at different interfaces for either case (human or machine), you will discover that as the function of the circuit […]
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Linear Feedback Shift Registers One of the most interesting logic devices you can work with is the ‘‘linear feedback shift register’’ (‘‘LFSR’’). It is built from a shift register along with two or more XOR gates modifying the contents of the register as shown in Fig. 9-12. This circuit can be used to ‘‘pseudo-randomize’’ data, […]
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Complex Sequential Circuits As the saying goes: ‘‘You now know enough to be dangerous.’’ You should be fairly comfortable with working with logic functions and equations, have an understanding of electronics and how to interface logic chips (of different families together), understand the basics of memory and have gone through a number of clocking schemes. […]
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Crystals and Ceramic Resonators For the best clock accuracy, a quartz crystal should be used in an oscillator circuit like the one shown in Fig. 8-13. A quartz crystal is a piezoelectric device that provides a constant delay between one side of the piece of quartz within the part to the other. The term piezoelectric […]
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Oscillators In the introduction to the previous chapter of this book, I presented you with a simple block diagram of a ‘‘complete’’ digital electronic device: the digital clock. This device has all three of the necessary components for a functional, ‘‘stand alone’’ device: combinatorial logic for converting binary data as required; a memory function which […]
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Test for Part One Do not refer to the text when taking this test. You may draw diagrams or use a calculator if necessary. A good score is at least 38 correct answers. Answers are in the back of the book. It’s best to have a friend check your score the first time so you […]
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