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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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20th May 2014, 9:13 pm | #1 |
Heptode
Join Date: Dec 2011
Location: Mayabeque, Cuba
Posts: 617
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D226 Diode (Silicon or Germanium)
Hello
Since I started to enjoy electronics, I have always use the D226 Soviet diode. It has been available in Cuba for years as almost all the vintage Soviet equipment used it. I have always thought that it was a Silicon diode, but now I read on radiomuseum.org that it is a Germanium diode http://www.radiomuseum.org/tubes/tube_d226.html So I made some test, cause I have always seen a voltage drop of 0.6 to 0.8 volts on this kind of diodes. I measure the voltage drop as I passed a current throught it. With 5mA it dropped 0,55V and with 40mA, it dropped 0,8V. It behaves as a Silicon diode but with some differences. I did the same test wit a KD202 diode (which I know is a Silicon diode, due to the prefix K [кремний]) and it dropped between 0,58 and 0,65V with the same variation of current. AFAIK, Germanium P-N junctions drop 0,2 to 0,3V when forward biased. So, I think there are several possibilities here: 1.) It is a Silicon diode. 2.) It is a special kind of Germanium diode 3.) It is three Germanium diodes in series. Any help about this? Thanks in advance
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20th May 2014, 10:25 pm | #2 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,969
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Re: D226 Diode (Silicon or Germanium)
It is behaving like a silicon diode, and it looks like an early silicon rectifier physically, but the current rating (300mA) is low for a silicon rectifier.
I think the most probable explanation is that the radiomuseum information is incorrect, but that's just a guess. |
23rd May 2014, 1:44 pm | #3 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: D226 Diode (Silicon or Germanium)
I would go with that guess too. Only the original datasheets could confirm what is the case.
In a 3rd party reference table found at http://www.datasheetarchive.com/dlma...870000-135.pdf it is listed as an Si* diode. Unfortunately, it isn't mentioned what the * refers to. |
23rd May 2014, 5:04 pm | #4 |
Heptode
Join Date: Dec 2011
Location: Mayabeque, Cuba
Posts: 617
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Re: D226 Diode (Silicon or Germanium)
I have a Catalog of Russian Component on .DJVU format which state that one of the Western equivalents of the D226 should be the: BAW14, MC030, MC51 and PS633; among others. All of this diodes are Silicons (I have found that the characteristics are not really equivalent according to the links bellow)
http://americanmicrosemi.com/informa...c/?ss_pn=BAW14 http://americanmicrosemi.com/informa...c/?ss_pn=MC030 http://americanmicrosemi.com/informa...ec/?ss_pn=MC51 http://americanmicrosemi.com/informa...c/?ss_pn=PS633 The Russian Catalog can be downloaded here: http://radiosit.ru/news/diody_tirist...011-10-26-1788
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29th May 2014, 3:16 pm | #5 |
Heptode
Join Date: Dec 2011
Location: Mayabeque, Cuba
Posts: 617
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Re: D226 Diode (Silicon or Germanium)
It seems that definitively it is a Silicon diode. A friend of mine send me this yesterday (I couldn't see it till today) on HTML format. He said it was from a Russian page that no longer exist. I convert it to PDF to show it here.
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29th May 2014, 6:53 pm | #6 |
Administrator
Join Date: Dec 2002
Location: Cardiff
Posts: 9,073
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Re: D226 Diode (Silicon or Germanium)
I've grabbed a copy for the data section on my free Vintage Radio Info website http://www.vintage-radio.info/data - I hope you don't mind!
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29th May 2014, 7:35 pm | #7 |
Heptode
Join Date: Dec 2011
Location: Mayabeque, Cuba
Posts: 617
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Re: D226 Diode (Silicon or Germanium)
Why should I?
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29th May 2014, 9:39 pm | #8 |
Nonode
Join Date: Oct 2008
Location: Warsaw, Poland and Cambridge, UK
Posts: 2,681
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Re: D226 Diode (Silicon or Germanium)
I'd guess that it's a silicon diode, but not a very good one, hence the extra forward voltage drop. It may have a high internal resistance due to some property of the junction or the way the wires are attached.
Chris
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