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Recommendations for Diode Resources

On this page you can find some resources that introduce you to diodes. As a prerequisite for understanding how they work together with other circuit elements, you should have a basic knowledge of elementary DC circuits - you might want to have a look at some resources on basic linear circuit analysis. Of course, the diode is a very nonlinear element, and calculating the exact values for voltage and current can be quite difficult (and is better left to a program like SPICE). But you can get pretty far with the approximation that, when conducting, there is a voltage of 0.7 V across the diode (for the common silicon types). Then you can apply what you know about linear circuit analysis to calculate the values for the rest of the circuit.

You can find an easy introduction to diodes in Lessons In Electric Circuits (allaboutcircuits), in the chapter Diodes and Rectifiers. And if you are interested in the foundations of this and other semiconductor devices, please have a look at the chapter Solid-State Device Theory. Yes, the pages carry a label that they need proofreading, but I have seen that several readers have over the years made corrections which were mostly minor. So I don't think that there are many more remaining serious errors. In any case, if you should find anything that appears strange to you, you can report it in the subforum Feedback and Suggestions and you will usually receive an answer within a few hours or a day. This is much better than what you can expect when you have doubts while reading a textbook... Please note that this subforum is for corrections, if there is anything that you simply do not understand, you should post it another subforum, in General Electronics Chat.

The Diode Pages of Storr's Basic Electronics Tutorials offer a short introduction to semiconductor physics and pn junctions on page 1 and 2. The remaining pages contain good explanations of all kinds of diodes and their typical applications.

If you already know the basics and you want a short summary, you should have a look a Hyperphysics. The page about diodes shortly dicsusses forward and reverse biased PN-junctions and then shows the typical V-I curve of a diode. As for all pages of hyperphysics, there are lots of links you can follow from there, be it semiconductor concepts or the most common applications of diodes.

You can find some interesting details in Troubleshooting Analog Circuits, chapter 6 p.65 and appendix E p.196. Among other things Pease shows a semilog plot of the V-I curves of many diodes he measured (among them LEDs and the base-emitter diodes of transistors), clearly showing the different slopes of the diodes. Some other interesting facts about diodes and zeners are also discussed. Please note that when he praises the high reliability of LEDs, he is talking about small signalling LEDs. Lighting LEDs (not yet available in 1991 when the book was written) are not quite as reliable due to their high power density.

The chapter on diodes in Sedra / Smith offers an easy introduction and a detailed treatment of the standard applications, like the different kind of rectifiers and clamping circuits. Very interesting are the discussions of the different kind of models (ideal diode, constant 0.7 V drop, piecewise linear (Update: Missing in the 6th edition, but it was not very relevant anyway), exponential curve, small signal approximation). Though in practice you will most likely use the simple 0.7 V drop approximation, you will have to use these kind of models very often while studying. Not so much for diodes, but for more complicated devices like transistors. So it is good idea to learn about them using the simple diode as an example. As for all topics in Sedra / Smith, there are lots of examples and problems. NOTE: I am writing this based on the 5th edition of the book. In a week or so I will have a look at the current (6th) edition. According to the information at Amazon, there is now a separate chapter on semiconductor concepts. UPDATE (08 / 13 / 2011): In the 6th edition the chapter on semiconductors (p. 124 - 163) provides a nice introduction to the subject. Intrinsic and doped semiconductors are explained, the pn-junction is discussed in some detail, including the charge distribution for forward and reverse bias, a derivation of the exponential relation between I and V and capacitive effects. The analysis of circuits that contain diodes has not changed very much in the 6th edition.

You can find more details about semiconductors in the free lecture notes Microelectronic Devices and Circuits by Charles G. Sodini (MIT Open Course Ware). Diodes are covered in lectures 14 to 16.

In chapter 8 of the free ANALOG SEEKrets you can find some interesting information about all kinds of diodes: Silicon diodes, Germanium rectifiers, LEDs, rectifier diodes, Schottky and , Zener diodes, varicaps, PIN diodes, SRDs (Step Recovery Diodes), tunnel diodes and Gunn diodes.

Zener diodes are a special kind of diode. You can find lots of information about them in the free handbook TVS/Zener Theory and Design Considerations by ON Semiconductor.

For questions about diodes, a very good place is Physics Forums. There are several subforums where you could ask, but you will have the best chance for a good answer if you ask in the Homework / Engineering subforum (for homework questions) or in the Electrical Engineering subforum (if there is something you don't understand about diodes). It doesn't matter whether your question is more about the semiconductor foundations of diodes or more about their application in electronic circuits - there are members in these two subforums who know very much about both aspects.

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