[1476] Fake GE Diodes

Date: August 7th, 2013 | Comments : [6] | Categories: DIY.

Fake Ge diodes

According to my tests, these are fake germanium diodes that I just bought off Ebay from a Hong Kong seller.

I searched thoroughly and these looked good in the listing, so I bought them to verify. They turned out to be bogus. They are not germaniums but Schottky diodes! I only paid about $5 for 100 pieces so I’m not concerned about it, but you should be cautious if you are looking for diodes to purchase for a project.

There are numerous listings for germanium diodes on Ebay and many of them appear to be fakes. I have quite a few real germaniums that are known to be good, so I got out the semiconductor tester and measured the Vf of a large selection of different types.

You’ll see from the chart that the fakes had a quite low forward voltage – much less than any real germaniums. Also, the genuine Ge diodes had more variability in the voltages while the fakes were very consistent. Lastly, the fakes are physically too small. They look to be DO-35 package style while real germaniums are all the larger DO-7 package.


1N914 silicon

0.69
0.69
0.69
1N4148 silicon
0.69
0.69

1N5819 Schottky

0.28
0.24
1N5819 Schottky (Diodes Inc.)
0.28
0.28
0.28
0.28

BAT41 Schottky

0.61
0.61
0.61
0.61
BAT48 Schottky
0.30
0.30
0.30
0.30

2N404 B-E junction

0.37
0.41
0.35
0.35
1N60 germanium
0.67
0.63
0.67
0.67

OA1160 germanium

0.71
0.63
0.69
0.59
1N192 germanium
0.53
0.71
0.65
0.77

1N34a germanium (known good)

0.53
0.51
0.51
0.53
0.55
Fake 1N34a Ge diodes
0.24
0.24
0.26
0.24
0.24
0.26

Diodes


The fakes are at the top while the middle and bottom diode styles are the real thing. If you click on the picture, you can get a larger version of it, and the 1N60 markings can be seen on the bottom set. The fakes are unmarked.

 

6 Responses to “Fake GE Diodes”

[3955] jody Says: 12:51 am, August 9th, 2013

I just bought some “Germanium Diodes” that look exactly like this from ebay. Mmmmm, very suspect


[4101] Csaba Says: 12:47 am, August 23rd, 2013

I’ve bought a batch of 1n34a’s from Tayda Electronics, and they have .31V forward voltage (varying from .30V to .33V). I’m quite sure they are real, I don’t think anyone would deliberately produce real looking ones in DO-7 packaging. The ones in your post seem to be fakes though, I’ve not seen any germanium diodes in DO-35 packaging (which doesn’t mean there aren’t any around…)


[5614] MasterBlaster Says: 5:59 pm, January 1st, 2014

The simpliest way to check is any diode really Ge or not is to measure its reverse resistance by DMM.
Ge-diodes are conductive due to their leakage, but Shottky are not.


[339721] Joe Says: 1:34 am, November 7th, 2014

Yep,

DO-7 are Ge, DO-35 are Si (can be PN or Schottky, Vf tells them apart). That’s definitive these days, although once upon a time, Si diodes did also come in DO-7.

To add to the confusion, there are at least 2 or 3 manufacturers making Schottky diodes under olde Ge part numbers! So you can’t really blame the eBay vendors for getting confused too.

Finally, to say as above, that Vf is higher for Ge than Schottky, is untrue, it all depends on how much current you apply.

Finally, finally, it’s not uncommon for Ge diodes to have no explicit markings. I have some Russian ones whose identity is certain, but the only clue is the colour of the cathode band.


[759023] David Says: 2:14 am, November 24th, 2015

Does anyone know what exact diode they actually are?? They sound perfect in my circuit, and after testing multiple combos and symetrical sets they’re the ones going in. I’m bummed i don’t know the real model so i can buy a bunch of them!!


[766065] manlog mic Says: 1:37 pm, December 25th, 2015

while trying to fix my amplified h.t. small subwoofer I found a do35 part in the circuit that I was sure to be a diode but it has a light blu band in the center and a very thin black band close behind it, also at the DMM it does not show any continuity nor in ohms nor as diode… I wonder if anyone of you know which kind of part is it? thanks to any info…




 

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