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What are the general steps and things to know to choose the right diode for the right project?

user46629
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  • You need to include a schematic so we can see what you are trying to so. – tcrosley Jul 07 '14 at 02:06
  • Idk how, I'm new to this side. – user46629 Jul 07 '14 at 02:13
  • draw a schematic, take a picture or a screenshot, and upload it using the "Image" button. I don't think it could be any more simple – DerStrom8 Jul 07 '14 at 02:17
  • Like that Right there – user46629 Jul 07 '14 at 02:24
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    No, like this - [Rules and guidelines for drawing good schematics](http://electronics.stackexchange.com/questions/28251/rules-and-guidelines-for-drawing-good-schematics) . – Nick Alexeev Jul 07 '14 at 02:55
  • I'm just giving the general idea – user46629 Jul 07 '14 at 03:09
  • If people are going to criticize over a general question needing a general answer then tell me the answer on "how to delete a question?" Because all I want is the idea on how to know what diode to get, not go into detail on how it will work with me specific project. Just the basic step by step process on finding the right diode. – user46629 Jul 07 '14 at 03:13
  • Are you running 12V straight through the diode to ground? No wonder it's not working! You're probably destroying your diodes! Also, what is the anode of your bottom diode supposed to be connected to? Think you need to learn how to draw schematics before anyone can help you further – DerStrom8 Jul 07 '14 at 03:14
  • @user46629 (1) You don't need to worry about deleting the question. Automatic script deletes closed questions with negative score in 9 days. (2) A general answer to your general question is: "Please read chapters 1 through 3 of [The Art of Electronics by Horowitz & Hill](http://en.wikipedia.org/wiki/The_Art_of_Electronics) (or something equivalent)." – Nick Alexeev Jul 07 '14 at 03:49
  • There are many ways it could be looked at but very roughly diodes could be categorised as power, signal, voltage regulation, special. 'Special' covers diodes used in no diode applications (eg varicaps) or unusual applications (eg Shockley). Power diodes need to have voltage and current ratings to suit and package dissipations suited to heating experienced. Above say 400 Hz frequency response needs to be suitable and style of turnoff (eg "soft", "fast" ) may matter, and more. Reverse leakage characteristics matter for some types and conditions (eg Schottky at high temperatures) ... – Russell McMahon Jul 07 '14 at 04:07
  • Wikipedia: Avalanche Zener point-contact cat's whisker Constant current Esaki tunnel Gunn LED Laser Photodiodes PIN Schottky Super barrier diodes Gold-doped Snap-off Step recovery Stabistors Forward Reference Transient voltage suppression Varicap varactor Zener – Russell McMahon Jul 07 '14 at 04:19
  • Re above: | [Useful](http://techtronix5.blogspot.co.nz/2014/03/diodes.html). | [Also useful](http://sainiembedded.wordpress.com/2013/05/09/types-of-diode/), |[Unattributed coying - but useful](http://kelas-khusus-rangkasbitung-p2k-itbu.sepakbola.biz/_lain.php?_en=ENGLISH&_lain=1615), – Russell McMahon Jul 07 '14 at 04:23
  • ... | Signal diodes usually have V *& I specs that meet many applications and behaviour at frequency usually. matters more. | Voltage regulation (usually zener) power V I matter but reverse breakdown voltage is main spec. Temperature dependance matters. | Lots more could be said but that's a start. | [Wikipedia - good start](http://en.wikipedia.org/wiki/Diode), [Basic but useful](http://www.allaboutcircuits.com/vol_3/chpt_3/1.html), – Russell McMahon Jul 07 '14 at 04:26
  • @NickAlexeev - I agree with you - I did not note that it had been altered so significantly from original. | But / and/ so / ..., having been "improved", should it not now be reopened? – Russell McMahon Jul 07 '14 at 04:29
  • @RussellMcMahon Fine, I'll reopen it. Purely out of respect for you. – Nick Alexeev Jul 07 '14 at 04:30
  • @NickAlexeev I deleted my comment on the original question as I had not realised how much it had been changed by editing . [[You may read that as "I was wrong" :-) ] – Russell McMahon Jul 07 '14 at 04:30

1 Answers1

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The general answer is "read the datasheet and see if its specific parameters suit your specific project".

The difficulty in answering this question is that there are many parameters, and the application determines which parameters are relevant.

For example, if the diode will be reverse biased, parameters like reverse breakdown voltage and reverse leakage current are important. If it is going to be forward biased and large currents will be flowing, things like thermal resistance and forward voltage drop are important. If you are using it in some kind of small signal measurement then you might want to look at temperature dependencies and manufacturing tolerances of its parameters. This can go on and on.

apalopohapa
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