[Milsurplus] G11 Diode

[Bob kb8tq]

Hi

At least on the data sheet I found, the 1N451 has a Vf of 1V rated at 50 (not 500, but 50) ma. That’s a whopping big 
Vf for a germanium part. More or less, you could have 5 “normal” germanium diodes in series and meet that spec. 
I can’t find any capacitance data on the web for the diode. The part seems to be rated at 80mw of dissipation. That 
would suggest that the 500 ma forward current number is a bit suspect as is the designation “rectifier diode”. 

I’d say the 1N4007 is looking pretty good by comparison. The only issue might be capacitance. A high speed 
diode likely would be a bit lower in that regard.

Bob

> On Dec 3, 2017, at 3:07 AM, Jim Whartenby <antqradio at sbcglobal.net> wrote:
> 
> Ray
> Nick England shows some photos of a USM-26A aka FR-38B/U at
> http://www.virhistory.com/navy/test.htm <http://www.virhistory.com/navy/test.htm>
> Looks like CR203 through CR208 are 1N451 which is a Germanium diode with a PIV of 170 volts, leakage of 150uA @ 150 volts and a peak forward current of 500 mA.  Vf is 1 volt so one assumes that a silicon diode of similar PIV specs can easily replace it.
> Qbus?
> Jim
> 
> 
> 
> From: Ray Fantini <RAFANTINI at salisbury.edu <mailto:RAFANTINI at salisbury.edu>>
> To: "mrca at mailman.qth.net <mailto:mrca at mailman.qth.net>" <MRCA at mailman.qth.net <mailto:MRCA at mailman.qth.net>>; Military Surplus Mail List <milsurplus at mailman.qth.net <mailto:milsurplus at mailman.qth.net>> 
> Sent: Saturday, December 2, 2017 11:25 AM
> Subject: [Milsurplus] G11 Dioede
> 
> Ok so working on this FR38B/U frequency counter and running into an issue. They use lots of early Germanium diodes to trigger and provide faster switching times in most of the vacuum tube stages.  They have a part number of 212-G11A but I have not been able to find any information on them. Was thinking of replacing a lot of the week performing ones with 1N914 switching diodes but am a little concerned about voltage rating  but have to assume that the late fifties first generation G11 has to be a lower voltage ratting then a modern silicone diode?
> There is a panel that originally had a dozen diodes as spares in the unit but someone stole or used those years ago. They must have been a high failure rate device.
> 
> Ray F/KA3EKH
>  
>  
> 
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