Where to Identify Diodes?

Question

Hello again!I am forever indebted to  ;)Do you know of any website where I might be able to ID a few sets ofdiodes i've gotten in an assortment from futurlec?I've tried searching futurlec's site, just googling the part names, andalso some searches at  but i don't have any hits onanything. They're in little baggies, and someone in Thailand orAustralia wrote the part numbers on them with a Bluntie (which is theresult of a well-used Sharpie).If i make the assumption that everyone in the English-speaking world(except the U.S.) slashes their Zs to differentiate them from 2s, thepart numbers are all "2D400MW", with the only difference between thelittle baggies being the rated voltages (8.1v, 6.2v, 5.1v, 11v.. etc)They're tiny, and they're glass, so there aren't any markings on thediodes themselves. I've never seen diodes this small and they're kindafascinating. I always thought glass casings was common to Ge diodes butthat was just an assumption, not an established fact....Any input or pointers would be very appreciated...thanks!-jared

Roger Johansson · Accepted Answer

I made the opposite assumption, removed the MW suffix, and searched for ZD400 diode, and found this pdf file

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See page 29

It lists zd400 as a zener diode, and it seems to fit your description of different voltages.

You can test if they really are zener diodes by sending a current of say

20mA through them and measure the voltage over the diode.

In this document they are listed as 1/2 Watt zener diodes, but don't trust that wattage number too much, your diodes may be a later or different version.

The suffix I removed, MW, can mean another wattage/package. But you can test run a few to find out how much power they actually can handle before burning up.

Roger Johansson · Answer

Oooops, just realized I made a mistake. ZD400 in this file is a location, not a component number.

Well, you can use my other advice about testing them anyway, and I think you will find that they are zener diodes, with a certain voltage and wattage which you can easily measure, and that's all the data you need to use them.

Terry Pinnell · Answer

Agreed, 'ZD400MW' plainly means 'Zener diode, 400 mW'.-- Terry PinnellHobbyist, West Sussex, UK

phaeton · Answer

Boy, don't i feel like a dolt...Thanks Terry...-jared

Roger Johansson · Answer

Finally, somebody who can read. Why didn't I think of that.The person who marked his bags of diodes simply marked them with whatthey are, it is not a component number code. Thanks.-- Roger J.

Fred Abse · Answer

Brits don'tAussies don'tCanucks (English speaking ones) don'tIn fact, I can't think of an English speaking country that I've hadanything to do with that does.-- Then there's duct tape ...               (Garrison Keillor)

To be, or not to be, that in t · Answer

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phaeton · Answer

Hey, thanks for that link.  I went up a couple of levels on the URL andwouldn't you know there's all kinds of interesting stuff there ;)I appreciate everyone's responses...-jared

Where to Identify Diodes?

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