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dsavitsk 29th June 2006 06:46 AM

HV Diode Selection
I am putting together a power supply that needs to give about 24mA at about 210V. I happen to have around a 125-0-125 transformer and an EZ81, so I thought I'd use these in conjunction with 2 silicon diodes to make a bridge rectifier. Does anyone have any suggestion of what to look for in terms of diodes to use. Digikey lists lots of D0-41 package ultra-fast diodes that are well over 800V. Does the choice matter beyond this? Any concerns with heat from this package? Anything else to concern myself with with a hybrid bridge?

DigitalJunkie 29th June 2006 07:30 AM

1N4007 (or UF4007) should be plenty beefy.
Of course you can shoot for a higher voltage,current,etc. if it pleases you.

SHiFTY 29th June 2006 01:14 PM

I had a couple of UF4007 go short circuit on me, so I never use them now.

Actually I had much better luck with plain old IN5408. 800V, 3A, what more do you need.

arnoldc 29th June 2006 04:08 PM

I use FR107 and have not had any failure, so far.

kevinkr 29th June 2006 05:16 PM

I've used UF4007 for quite a few years and never had one fail..
Given the rating of the EZ81 this or the 1N4007 ought to be good enough..

The soft turn off/fast recovery characteristic of the tube rectifier imho makes the use of fast silicon diodes unnecessary.

I'd say use whatever you can get at a reasonable cost with a PIV rating of at least 800V to allow for line transients.

I'm not convinced that I have ever heard a real difference between comparable diodes fast or otherwise. In terms of RF noise it definitely does make a difference that can be measured. RC snubbers incidentally can take care of this too, and are good practice for high voltage rectifier stacks regardless of diode type used...

Edits: still learning to spell I guess.. LOL

Tom Bavis 29th June 2006 08:20 PM

ONSemiconductor MUR4100E (1000V/4A) are rated for reverse avalanche energy - they will withstand huge overvoltage spikes. And I think they're .80 cents apiece...

pengboon 10th September 2006 09:34 AM

Has anyone used these with good results? I've just had a UF4007 failure and looking to use some better parts.


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