Author Topic: Diode replacement  (Read 1681 times)

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Offline Daxxin

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Diode replacement
« on: December 25, 2016, 09:41:01 am »
need to replace 1N4937 at moment i only have BYV26E wathing datashet seems to be similar ...its ok ?
 

Offline David Hess

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Re: Diode replacement
« Reply #1 on: December 25, 2016, 01:43:09 pm »
The 1N4937 is a 600V 1A 200ns fast recovery rectifier.  The BYV26E is a 1000V 1A 75ns ultra-fast recovery rectifier.

The BYV26E is not really a substitute for the 1N4937 because of its significantly larger forward voltage drop however that will not matter in a high voltage circuit which is the only reason to use a 600V 1N4937 instead of a lower voltage alternative.

« Last Edit: December 25, 2016, 01:57:17 pm by David Hess »
 

Offline Daxxin

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Re: Diode replacement
« Reply #2 on: December 26, 2016, 06:30:44 am »
thanks its working ,  very low voltage 18v hf trafo output i guess there no big difference no idea why they using that hv diode in the original
circuit maybe huge stock.
 

Offline SeanB

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Re: Diode replacement
« Reply #3 on: December 26, 2016, 07:07:15 am »
Price wise there is no difference in the low voltage or high voltage variant, and often the high voltage version is a lot cheaper because of volume and because the process control is tight enough that all test out to pass.

Your 1N4001 and 1N4007 can come from the same die, and have the same breakdown voltage as well, simply because the majority were marked as 1N4007 as they tested out that way, while they had an order for a few hundred 1N4001 that were simply branded that way, as the diodes tested out to break down at more than 100V. More expensive, simply from the small run.

Silicon diodes are a very low cost item for the common types, so making them all to the same spec for a range and simply doing a relabel is cheaper, as you only have to do a single test cycle, and any that fail are scrapped and sold unlabelled and unmarked. Those diodes are then bought as scrap, and used after some basic sorting, by the cheapest manufacturers to make the cheap knockoffs, as they want to cut cost, and test all incoming as they know they will get fakes and recycled components.
 

Offline David Hess

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Re: Diode replacement
« Reply #4 on: December 26, 2016, 07:14:39 am »
They might have used it just to limit the number of separate parts kept in stock.  I do the same thing; why keep all of the different 1N4933 series of diodes, 50 to 600 volts, when the 1N4937, 600 volts, can almost always be used in place of all of them? 

The BYV26E is really intended for a different set of applications like high voltage high efficiency switching power supplies but in many cases like Sigmund Freud said, a diode is just a diode.
 


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